diff --git a/accessible/base/DocManager.cpp b/accessible/base/DocManager.cpp
index 08db38e6569..6fa97d62972 100644
--- a/accessible/base/DocManager.cpp
+++ b/accessible/base/DocManager.cpp
@@ -190,11 +190,11 @@ DocManager::OnStateChange(nsIWebProgress* aWebProgress,
   aWebProgress->GetDOMWindow(getter_AddRefs(DOMWindow));
   NS_ENSURE_STATE(DOMWindow);
 
-  nsCOMPtr<nsIDOMDocument> DOMDocument;
-  DOMWindow->GetDocument(getter_AddRefs(DOMDocument));
-  NS_ENSURE_STATE(DOMDocument);
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(DOMWindow);
+  MOZ_ASSERT(piWindow);
 
-  nsCOMPtr<nsIDocument> document(do_QueryInterface(DOMDocument));
+  nsCOMPtr<nsIDocument> document = piWindow->GetDoc();
+  NS_ENSURE_STATE(document);
 
   // Document was loaded.
   if (aStateFlags & STATE_STOP) {
diff --git a/accessible/generic/ApplicationAccessible.cpp b/accessible/generic/ApplicationAccessible.cpp
index 4a2f1a38755..69537e26b82 100644
--- a/accessible/generic/ApplicationAccessible.cpp
+++ b/accessible/generic/ApplicationAccessible.cpp
@@ -1,5 +1,5 @@
-/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
-/* vim:expandtab:shiftwidth=4:tabstop=4:
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
  */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
@@ -193,12 +193,10 @@ ApplicationAccessible::CacheChildren()
   while (hasMore) {
     nsCOMPtr<nsISupports> window;
     windowEnumerator->GetNext(getter_AddRefs(window));
-    nsCOMPtr<nsIDOMWindow> DOMWindow = do_QueryInterface(window);
+    nsCOMPtr<nsPIDOMWindow> DOMWindow = do_QueryInterface(window);
     if (DOMWindow) {
-      nsCOMPtr<nsIDOMDocument> DOMDocument;
-      DOMWindow->GetDocument(getter_AddRefs(DOMDocument));
-      if (DOMDocument) {
-        nsCOMPtr<nsIDocument> docNode(do_QueryInterface(DOMDocument));
+      nsCOMPtr<nsIDocument> docNode = DOMWindow->GetDoc();
+      if (docNode) {
         GetAccService()->GetDocAccessible(docNode); // ensure creation
       }
     }
diff --git a/accessible/generic/ImageAccessible.cpp b/accessible/generic/ImageAccessible.cpp
index 0f2f7ca08db..cd9a7f44378 100644
--- a/accessible/generic/ImageAccessible.cpp
+++ b/accessible/generic/ImageAccessible.cpp
@@ -133,13 +133,12 @@ ImageAccessible::DoAction(uint8_t aIndex)
 
   nsIDocument* document = mContent->OwnerDoc();
   nsCOMPtr<nsPIDOMWindow> piWindow = document->GetWindow();
-  nsCOMPtr<nsIDOMWindow> win = do_QueryInterface(piWindow);
-  if (!win)
+  if (!piWindow)
     return false;
 
-  nsCOMPtr<nsIDOMWindow> tmp;
-  return NS_SUCCEEDED(win->Open(spec, EmptyString(), EmptyString(),
-                                getter_AddRefs(tmp)));
+  nsCOMPtr<nsPIDOMWindow> tmp;
+  return NS_SUCCEEDED(piWindow->Open(spec, EmptyString(), EmptyString(),
+                                     getter_AddRefs(tmp)));
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/accessible/generic/RootAccessible.cpp b/accessible/generic/RootAccessible.cpp
index 01d7153f32e..1989b119468 100644
--- a/accessible/generic/RootAccessible.cpp
+++ b/accessible/generic/RootAccessible.cpp
@@ -486,11 +486,9 @@ RootAccessible::RelationByType(RelationType aType)
   nsPIDOMWindow* rootWindow = mDocumentNode->GetWindow();
   if (rootWindow) {
     nsCOMPtr<nsIDOMWindow> contentWindow = nsGlobalWindow::Cast(rootWindow)->GetContent();
-    if (contentWindow) {
-      nsCOMPtr<nsIDOMDocument> contentDOMDocument;
-      contentWindow->GetDocument(getter_AddRefs(contentDOMDocument));
-      nsCOMPtr<nsIDocument> contentDocumentNode =
-        do_QueryInterface(contentDOMDocument);
+    nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(contentWindow);
+    if (piWindow) {
+      nsCOMPtr<nsIDocument> contentDocumentNode = piWindow->GetDoc();
       if (contentDocumentNode) {
         DocAccessible* contentDocument =
           GetAccService()->GetDocAccessible(contentDocumentNode);
diff --git a/accessible/windows/msaa/moz.build b/accessible/windows/msaa/moz.build
index 42469ada2d3..d3dfce81011 100644
--- a/accessible/windows/msaa/moz.build
+++ b/accessible/windows/msaa/moz.build
@@ -56,6 +56,7 @@ LOCAL_INCLUDES += [
     '/accessible/xpcom',
     '/accessible/xul',
     '/dom/base',
+    '/layout/style',
 ]
 
 include('/ipc/chromium/chromium-config.mozbuild')
diff --git a/accessible/windows/msaa/nsWinUtils.cpp b/accessible/windows/msaa/nsWinUtils.cpp
index 96a2ddb32f6..15a9701a5e7 100644
--- a/accessible/windows/msaa/nsWinUtils.cpp
+++ b/accessible/windows/msaa/nsWinUtils.cpp
@@ -15,13 +15,15 @@
 #include "mozilla/Preferences.h"
 #include "nsArrayUtils.h"
 #include "nsIArray.h"
+#include "nsICSSDeclaration.h"
 #include "nsIDocument.h"
 #include "nsIDocShellTreeItem.h"
-#include "nsIDOMElement.h"
+#include "mozilla/dom/Element.h"
 #include "nsXULAppAPI.h"
 
 using namespace mozilla;
 using namespace mozilla::a11y;
+using mozilla::dom::Element;
 
 // Window property used by ipc related code in identifying accessible
 // tab windows.
@@ -43,15 +45,18 @@ nsWinUtils::GetComputedStyleDeclaration(nsIContent* aContent)
     return nullptr;
 
   // Returns number of items in style declaration
-  nsCOMPtr<nsIDOMWindow> window =
+  nsCOMPtr<nsPIDOMWindow> window =
     do_QueryInterface(elm->OwnerDoc()->GetWindow());
   if (!window)
     return nullptr;
 
-  nsCOMPtr<nsIDOMCSSStyleDeclaration> cssDecl;
-  nsCOMPtr<nsIDOMElement> domElement(do_QueryInterface(elm));
-  window->GetComputedStyle(domElement, EmptyString(), getter_AddRefs(cssDecl));
-  return cssDecl.forget();
+  ErrorResult dummy;
+  nsCOMPtr<nsICSSDeclaration> cssDecl;
+  nsCOMPtr<Element> domElement(do_QueryInterface(elm));
+  cssDecl = window->GetComputedStyle(*domElement, EmptyString(), dummy);
+  nsCOMPtr<nsIDOMCSSStyleDeclaration> domDecl = do_QueryInterface(cssDecl);
+  dummy.SuppressException();
+  return domDecl.forget();
 }
 
 bool
diff --git a/b2g/app/b2g.js b/b2g/app/b2g.js
index c3fa5a8fa8e..2caa3e0e67c 100644
--- a/b2g/app/b2g.js
+++ b/b2g/app/b2g.js
@@ -1025,6 +1025,7 @@ pref("apz.fling_curve_function_x2", "0.80");
 pref("apz.fling_curve_function_y2", "1.0");
 pref("apz.fling_curve_threshold_inches_per_ms", "0.01");
 pref("apz.fling_friction", "0.0019");
+pref("apz.fling_snap_friction", "0.015");
 pref("apz.max_velocity_inches_per_ms", "0.07");
 pref("apz.touch_start_tolerance", "0.1");
 
diff --git a/b2g/chrome/content/settings.js b/b2g/chrome/content/settings.js
index 14beb13937c..f55aef186e6 100644
--- a/b2g/chrome/content/settings.js
+++ b/b2g/chrome/content/settings.js
@@ -121,7 +121,15 @@ SettingsListener.observe('language.current', 'en-US', function(value) {
   Services.prefs.setCharPref(prefName, value);
 
   if (shell.hasStarted() == false) {
-    shell.bootstrap();
+    // On b2gdroid at first run we need to synchronize our wallpaper with
+    // Android one's before bootstrapping.
+    if (AppConstants.MOZ_B2GDROID) {
+      Cc["@mozilla.org/b2g/b2gdroid-setup;1"]
+        .getService().wrappedJSObject.setWallpaper()
+        .then(() => { shell.bootstrap(); });
+    } else {
+      shell.bootstrap();
+    }
   }
 });
 
diff --git a/b2g/config/aries/sources.xml b/b2g/config/aries/sources.xml
index 85efb1e04c4..3ae32b10301 100644
--- a/b2g/config/aries/sources.xml
+++ b/b2g/config/aries/sources.xml
@@ -15,7 +15,7 @@
   <project name="platform_build" path="build" remote="b2g" revision="8d83715f08b7849f16a0dfc88f78d5c3a89c0a54">
     <copyfile dest="Makefile" src="core/root.mk"/>
   </project>
-  <project name="gaia" path="gaia" remote="mozillaorg" revision="b564b21e08ffc3e4962f08850843c7482932ee7b"/>
+  <project name="gaia" path="gaia" remote="mozillaorg" revision="b6ede3d0fdec5fc922e9ca3401e60db461bf705c"/>
   <project name="fake-libdvm" path="dalvik" remote="b2g" revision="d50ae982b19f42f0b66d08b9eb306be81687869f"/>
   <project name="fake-qemu-kernel" path="prebuilts/qemu-kernel" remote="b2g" revision="939b377d55a2f081d94029a30a75d05e5a20daf3"/>
   <project name="gonk-misc" path="gonk-misc" remote="b2g" revision="956700d9754349b630a34551750ae6353614b6aa"/>
diff --git a/b2g/config/dolphin/sources.xml b/b2g/config/dolphin/sources.xml
index 2d6486fbcb6..f5171fed4e0 100644
--- a/b2g/config/dolphin/sources.xml
+++ b/b2g/config/dolphin/sources.xml
@@ -15,7 +15,7 @@
   <project name="platform_build" path="build" remote="b2g" revision="8d83715f08b7849f16a0dfc88f78d5c3a89c0a54">
     <copyfile dest="Makefile" src="core/root.mk"/>
   </project>
-  <project name="gaia" path="gaia" remote="mozillaorg" revision="b564b21e08ffc3e4962f08850843c7482932ee7b"/>
+  <project name="gaia" path="gaia" remote="mozillaorg" revision="b6ede3d0fdec5fc922e9ca3401e60db461bf705c"/>
   <project name="fake-libdvm" path="dalvik" remote="b2g" revision="d50ae982b19f42f0b66d08b9eb306be81687869f"/>
   <project name="fake-qemu-kernel" path="prebuilts/qemu-kernel" remote="b2g" revision="939b377d55a2f081d94029a30a75d05e5a20daf3"/>
   <project name="gonk-misc" path="gonk-misc" remote="b2g" revision="956700d9754349b630a34551750ae6353614b6aa"/>
diff --git a/b2g/config/emulator-ics/sources.xml b/b2g/config/emulator-ics/sources.xml
index 4bad2cac68e..bc8c59db790 100644
--- a/b2g/config/emulator-ics/sources.xml
+++ b/b2g/config/emulator-ics/sources.xml
@@ -19,7 +19,7 @@
     <copyfile dest="Makefile" src="core/root.mk"/>
   </project>
   <project name="fake-dalvik" path="dalvik" remote="b2g" revision="ca1f327d5acc198bb4be62fa51db2c039032c9ce"/>
-  <project name="gaia.git" path="gaia" remote="mozillaorg" revision="b564b21e08ffc3e4962f08850843c7482932ee7b"/>
+  <project name="gaia.git" path="gaia" remote="mozillaorg" revision="b6ede3d0fdec5fc922e9ca3401e60db461bf705c"/>
   <project name="gonk-misc" path="gonk-misc" remote="b2g" revision="956700d9754349b630a34551750ae6353614b6aa"/>
   <project name="rilproxy" path="rilproxy" remote="b2g" revision="5ef30994f4778b4052e58a4383dbe7890048c87e"/>
   <project name="platform_hardware_ril" path="hardware/ril" remote="b2g" revision="4ace9aaee0e048dfda11bb787646c59982a3dc80"/>
diff --git a/b2g/config/emulator-jb/sources.xml b/b2g/config/emulator-jb/sources.xml
index b84235e07e8..027064b557d 100644
--- a/b2g/config/emulator-jb/sources.xml
+++ b/b2g/config/emulator-jb/sources.xml
@@ -17,7 +17,7 @@
   </project>
   <project name="rilproxy" path="rilproxy" remote="b2g" revision="5ef30994f4778b4052e58a4383dbe7890048c87e"/>
   <project name="fake-libdvm" path="dalvik" remote="b2g" revision="d50ae982b19f42f0b66d08b9eb306be81687869f"/>
-  <project name="gaia" path="gaia" remote="mozillaorg" revision="b564b21e08ffc3e4962f08850843c7482932ee7b"/>
+  <project name="gaia" path="gaia" remote="mozillaorg" revision="b6ede3d0fdec5fc922e9ca3401e60db461bf705c"/>
   <project name="gonk-misc" path="gonk-misc" remote="b2g" revision="956700d9754349b630a34551750ae6353614b6aa"/>
   <project name="moztt" path="external/moztt" remote="b2g" revision="3b9a47b517d345b8d98bc7f787b9a6c2f51ca75d"/>
   <project name="apitrace" path="external/apitrace" remote="apitrace" revision="0c28789b9957913be975eb002a22323f93585d4c"/>
diff --git a/b2g/config/emulator-kk/sources.xml b/b2g/config/emulator-kk/sources.xml
index 2c5b5589377..40fc38834e2 100644
--- a/b2g/config/emulator-kk/sources.xml
+++ b/b2g/config/emulator-kk/sources.xml
@@ -15,7 +15,7 @@
   <project name="platform_build" path="build" remote="b2g" revision="8d83715f08b7849f16a0dfc88f78d5c3a89c0a54">
     <copyfile dest="Makefile" src="core/root.mk"/>
   </project>
-  <project name="gaia" path="gaia" remote="mozillaorg" revision="b564b21e08ffc3e4962f08850843c7482932ee7b"/>
+  <project name="gaia" path="gaia" remote="mozillaorg" revision="b6ede3d0fdec5fc922e9ca3401e60db461bf705c"/>
   <project name="fake-libdvm" path="dalvik" remote="b2g" revision="d50ae982b19f42f0b66d08b9eb306be81687869f"/>
   <project name="gonk-misc" path="gonk-misc" remote="b2g" revision="956700d9754349b630a34551750ae6353614b6aa"/>
   <project name="librecovery" path="librecovery" remote="b2g" revision="1b3591a50ed352fc6ddb77462b7b35d0bfa555a3"/>
diff --git a/b2g/config/emulator-l/sources.xml b/b2g/config/emulator-l/sources.xml
index 4350c01884f..ac6902f8cfe 100644
--- a/b2g/config/emulator-l/sources.xml
+++ b/b2g/config/emulator-l/sources.xml
@@ -15,7 +15,7 @@
   <project name="platform_build" path="build" remote="b2g" revision="c9d4fe680662ee44a4bdea42ae00366f5df399cf">
     <copyfile dest="Makefile" src="core/root.mk"/>
   </project>
-  <project name="gaia" path="gaia" remote="mozillaorg" revision="b564b21e08ffc3e4962f08850843c7482932ee7b"/>
+  <project name="gaia" path="gaia" remote="mozillaorg" revision="b6ede3d0fdec5fc922e9ca3401e60db461bf705c"/>
   <project name="fake-libdvm" path="dalvik" remote="b2g" revision="d50ae982b19f42f0b66d08b9eb306be81687869f"/>
   <project name="gonk-misc" path="gonk-misc" remote="b2g" revision="956700d9754349b630a34551750ae6353614b6aa"/>
   <project name="librecovery" path="librecovery" remote="b2g" revision="1b3591a50ed352fc6ddb77462b7b35d0bfa555a3"/>
diff --git a/b2g/config/emulator/sources.xml b/b2g/config/emulator/sources.xml
index 4bad2cac68e..bc8c59db790 100644
--- a/b2g/config/emulator/sources.xml
+++ b/b2g/config/emulator/sources.xml
@@ -19,7 +19,7 @@
     <copyfile dest="Makefile" src="core/root.mk"/>
   </project>
   <project name="fake-dalvik" path="dalvik" remote="b2g" revision="ca1f327d5acc198bb4be62fa51db2c039032c9ce"/>
-  <project name="gaia.git" path="gaia" remote="mozillaorg" revision="b564b21e08ffc3e4962f08850843c7482932ee7b"/>
+  <project name="gaia.git" path="gaia" remote="mozillaorg" revision="b6ede3d0fdec5fc922e9ca3401e60db461bf705c"/>
   <project name="gonk-misc" path="gonk-misc" remote="b2g" revision="956700d9754349b630a34551750ae6353614b6aa"/>
   <project name="rilproxy" path="rilproxy" remote="b2g" revision="5ef30994f4778b4052e58a4383dbe7890048c87e"/>
   <project name="platform_hardware_ril" path="hardware/ril" remote="b2g" revision="4ace9aaee0e048dfda11bb787646c59982a3dc80"/>
diff --git a/b2g/config/flame-kk/sources.xml b/b2g/config/flame-kk/sources.xml
index c576c40e9c0..becd238c5a5 100644
--- a/b2g/config/flame-kk/sources.xml
+++ b/b2g/config/flame-kk/sources.xml
@@ -15,7 +15,7 @@
   <project name="platform_build" path="build" remote="b2g" revision="8d83715f08b7849f16a0dfc88f78d5c3a89c0a54">
     <copyfile dest="Makefile" src="core/root.mk"/>
   </project>
-  <project name="gaia" path="gaia" remote="mozillaorg" revision="b564b21e08ffc3e4962f08850843c7482932ee7b"/>
+  <project name="gaia" path="gaia" remote="mozillaorg" revision="b6ede3d0fdec5fc922e9ca3401e60db461bf705c"/>
   <project name="fake-libdvm" path="dalvik" remote="b2g" revision="d50ae982b19f42f0b66d08b9eb306be81687869f"/>
   <project name="fake-qemu-kernel" path="prebuilts/qemu-kernel" remote="b2g" revision="939b377d55a2f081d94029a30a75d05e5a20daf3"/>
   <project name="gonk-misc" path="gonk-misc" remote="b2g" revision="956700d9754349b630a34551750ae6353614b6aa"/>
diff --git a/b2g/config/gaia.json b/b2g/config/gaia.json
index 554d1d53dcf..544c204746d 100644
--- a/b2g/config/gaia.json
+++ b/b2g/config/gaia.json
@@ -1,9 +1,9 @@
 {
     "git": {
-        "git_revision": "b564b21e08ffc3e4962f08850843c7482932ee7b", 
+        "git_revision": "b6ede3d0fdec5fc922e9ca3401e60db461bf705c", 
         "remote": "https://git.mozilla.org/releases/gaia.git", 
         "branch": ""
     }, 
-    "revision": "bc907981bd62560e8d0079244bdc32b1dfe98e36", 
+    "revision": "220b45ec153f267a2efc58275a30a665a4ec9e57", 
     "repo_path": "integration/gaia-central"
 }
diff --git a/b2g/config/nexus-4-kk/sources.xml b/b2g/config/nexus-4-kk/sources.xml
index a00bc8a72b9..0f438450f20 100644
--- a/b2g/config/nexus-4-kk/sources.xml
+++ b/b2g/config/nexus-4-kk/sources.xml
@@ -15,7 +15,7 @@
   <project name="platform_build" path="build" remote="b2g" revision="8d83715f08b7849f16a0dfc88f78d5c3a89c0a54">
     <copyfile dest="Makefile" src="core/root.mk"/>
   </project>
-  <project name="gaia" path="gaia" remote="mozillaorg" revision="b564b21e08ffc3e4962f08850843c7482932ee7b"/>
+  <project name="gaia" path="gaia" remote="mozillaorg" revision="b6ede3d0fdec5fc922e9ca3401e60db461bf705c"/>
   <project name="fake-libdvm" path="dalvik" remote="b2g" revision="d50ae982b19f42f0b66d08b9eb306be81687869f"/>
   <project name="fake-qemu-kernel" path="prebuilts/qemu-kernel" remote="b2g" revision="939b377d55a2f081d94029a30a75d05e5a20daf3"/>
   <project name="gonk-misc" path="gonk-misc" remote="b2g" revision="956700d9754349b630a34551750ae6353614b6aa"/>
diff --git a/b2g/config/nexus-4/sources.xml b/b2g/config/nexus-4/sources.xml
index e35768c89df..fbb6db6af61 100644
--- a/b2g/config/nexus-4/sources.xml
+++ b/b2g/config/nexus-4/sources.xml
@@ -18,7 +18,7 @@
   <project name="rilproxy" path="rilproxy" remote="b2g" revision="5ef30994f4778b4052e58a4383dbe7890048c87e"/>
   <project name="fake-libdvm" path="dalvik" remote="b2g" revision="d50ae982b19f42f0b66d08b9eb306be81687869f"/>
   <project name="fake-qemu-kernel" path="prebuilts/qemu-kernel" remote="b2g" revision="939b377d55a2f081d94029a30a75d05e5a20daf3"/>
-  <project name="gaia" path="gaia" remote="mozillaorg" revision="b564b21e08ffc3e4962f08850843c7482932ee7b"/>
+  <project name="gaia" path="gaia" remote="mozillaorg" revision="b6ede3d0fdec5fc922e9ca3401e60db461bf705c"/>
   <project name="gonk-misc" path="gonk-misc" remote="b2g" revision="956700d9754349b630a34551750ae6353614b6aa"/>
   <project name="moztt" path="external/moztt" remote="b2g" revision="3b9a47b517d345b8d98bc7f787b9a6c2f51ca75d"/>
   <project name="apitrace" path="external/apitrace" remote="apitrace" revision="0c28789b9957913be975eb002a22323f93585d4c"/>
diff --git a/b2g/config/nexus-5-l/sources.xml b/b2g/config/nexus-5-l/sources.xml
index dc46bbdedcd..f663477d69b 100644
--- a/b2g/config/nexus-5-l/sources.xml
+++ b/b2g/config/nexus-5-l/sources.xml
@@ -15,7 +15,7 @@
   <project name="platform_build" path="build" remote="b2g" revision="c9d4fe680662ee44a4bdea42ae00366f5df399cf">
     <copyfile dest="Makefile" src="core/root.mk"/>
   </project>
-  <project name="gaia" path="gaia" remote="mozillaorg" revision="b564b21e08ffc3e4962f08850843c7482932ee7b"/>
+  <project name="gaia" path="gaia" remote="mozillaorg" revision="b6ede3d0fdec5fc922e9ca3401e60db461bf705c"/>
   <project name="fake-libdvm" path="dalvik" remote="b2g" revision="d50ae982b19f42f0b66d08b9eb306be81687869f"/>
   <project name="fake-qemu-kernel" path="prebuilts/qemu-kernel" remote="b2g" revision="939b377d55a2f081d94029a30a75d05e5a20daf3"/>
   <project name="gonk-misc" path="gonk-misc" remote="b2g" revision="956700d9754349b630a34551750ae6353614b6aa"/>
diff --git a/browser/base/content/abouthome/aboutHome.js b/browser/base/content/abouthome/aboutHome.js
index 4abb38fdf3d..352d534b325 100644
--- a/browser/base/content/abouthome/aboutHome.js
+++ b/browser/base/content/abouthome/aboutHome.js
@@ -357,7 +357,7 @@ function showDefaultSnippets()
 }
 
 function fitToWidth() {
-  if (window.scrollMaxX) {
+  if (window.scrollMaxX != window.scrollMinX) {
     document.body.setAttribute("narrow", "true");
   } else if (document.body.hasAttribute("narrow")) {
     document.body.removeAttribute("narrow");
diff --git a/browser/components/customizableui/CustomizableUI.jsm b/browser/components/customizableui/CustomizableUI.jsm
index e74815230dd..dfc6ead7ebe 100644
--- a/browser/components/customizableui/CustomizableUI.jsm
+++ b/browser/components/customizableui/CustomizableUI.jsm
@@ -4086,7 +4086,7 @@ OverflowableToolbar.prototype = {
 
     let child = this._target.lastChild;
 
-    while (child && this._target.scrollLeftMax > 0) {
+    while (child && this._target.scrollLeftMin != this._target.scrollLeftMax) {
       let prevChild = child.previousSibling;
 
       if (child.getAttribute("overflows") != "false") {
@@ -4166,7 +4166,7 @@ OverflowableToolbar.prototype = {
     if (!this._enabled)
       return;
 
-    if (this._target.scrollLeftMax > 0) {
+    if (this._target.scrollLeftMin != this._target.scrollLeftMax) {
       this.onOverflow();
     } else {
       this._moveItemsBackToTheirOrigin();
diff --git a/browser/components/places/content/browserPlacesViews.js b/browser/components/places/content/browserPlacesViews.js
index d444e4b3add..149e64a26f1 100644
--- a/browser/components/places/content/browserPlacesViews.js
+++ b/browser/components/places/content/browserPlacesViews.js
@@ -1181,7 +1181,7 @@ PlacesToolbar.prototype = {
   },
 
   updateOverflowStatus: function() {
-    if (this._rootElt.scrollLeftMax > 0) {
+    if (this._rootElt.scrollLeftMin != this._rootElt.scrollLeftMax) {
       this._onOverflow();
     } else {
       this._onUnderflow();
diff --git a/caps/BasePrincipal.cpp b/caps/BasePrincipal.cpp
index 01bec09b447..006bb320f56 100644
--- a/caps/BasePrincipal.cpp
+++ b/caps/BasePrincipal.cpp
@@ -340,9 +340,30 @@ BasePrincipal::GetCspJSON(nsAString& outCSPinJSON)
 }
 
 NS_IMETHODIMP
-BasePrincipal::GetIsNullPrincipal(bool* aIsNullPrincipal)
+BasePrincipal::GetIsNullPrincipal(bool* aResult)
 {
-  *aIsNullPrincipal = false;
+  *aResult = Kind() == eNullPrincipal;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+BasePrincipal::GetIsCodebasePrincipal(bool* aResult)
+{
+  *aResult = Kind() == eCodebasePrincipal;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+BasePrincipal::GetIsExpandedPrincipal(bool* aResult)
+{
+  *aResult = Kind() == eExpandedPrincipal;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+BasePrincipal::GetIsSystemPrincipal(bool* aResult)
+{
+  *aResult = Kind() == eSystemPrincipal;
   return NS_OK;
 }
 
diff --git a/caps/BasePrincipal.h b/caps/BasePrincipal.h
index 0c1c036ce1d..97ef77b0d2f 100644
--- a/caps/BasePrincipal.h
+++ b/caps/BasePrincipal.h
@@ -147,7 +147,10 @@ public:
   NS_IMETHOD GetCsp(nsIContentSecurityPolicy** aCsp) override;
   NS_IMETHOD SetCsp(nsIContentSecurityPolicy* aCsp) override;
   NS_IMETHOD GetCspJSON(nsAString& outCSPinJSON) override;
-  NS_IMETHOD GetIsNullPrincipal(bool* aIsNullPrincipal) override;
+  NS_IMETHOD GetIsNullPrincipal(bool* aResult) override;
+  NS_IMETHOD GetIsCodebasePrincipal(bool* aResult) override;
+  NS_IMETHOD GetIsExpandedPrincipal(bool* aResult) override;
+  NS_IMETHOD GetIsSystemPrincipal(bool* aResult) override;
   NS_IMETHOD GetJarPrefix(nsACString& aJarPrefix) final;
   NS_IMETHOD GetOriginAttributes(JSContext* aCx, JS::MutableHandle<JS::Value> aVal) final;
   NS_IMETHOD GetOriginSuffix(nsACString& aOriginSuffix) final;
@@ -171,6 +174,15 @@ public:
   uint32_t UserContextId() const { return mOriginAttributes.mUserContextId; }
   bool IsInBrowserElement() const { return mOriginAttributes.mInBrowser; }
 
+  enum PrincipalKind {
+    eNullPrincipal,
+    eCodebasePrincipal,
+    eExpandedPrincipal,
+    eSystemPrincipal
+  };
+
+  virtual PrincipalKind Kind() = 0;
+
 protected:
   virtual ~BasePrincipal();
 
diff --git a/caps/nsIPrincipal.idl b/caps/nsIPrincipal.idl
index 352ecc0b9cb..7263d5eb853 100644
--- a/caps/nsIPrincipal.idl
+++ b/caps/nsIPrincipal.idl
@@ -20,7 +20,7 @@ interface nsIContentSecurityPolicy;
 [ptr] native JSPrincipals(JSPrincipals);
 [ptr] native PrincipalArray(nsTArray<nsCOMPtr<nsIPrincipal> >);
 
-[scriptable, builtinclass, uuid(a083acd0-1ebf-4585-85ab-08cfdd9c96bd)]
+[scriptable, builtinclass, uuid(86e5fd29-dccb-4547-8918-f224005479a0)]
 interface nsIPrincipal : nsISerializable
 {
     /**
@@ -280,11 +280,26 @@ interface nsIPrincipal : nsISerializable
     [infallible] readonly attribute boolean unknownAppId;
 
     /**
-     * Returns true iff this principal is a null principal (corresponding to an
+     * Returns true iff this is a null principal (corresponding to an
      * unknown, hence assumed minimally privileged, security context).
      */
     [infallible] readonly attribute boolean isNullPrincipal;
 
+    /**
+     * Returns true iff this principal corresponds to a codebase origin.
+     */
+    [infallible] readonly attribute boolean isCodebasePrincipal;
+
+    /**
+     * Returns true iff this is an expanded principal.
+     */
+    [infallible] readonly attribute boolean isExpandedPrincipal;
+
+    /**
+     * Returns true iff this is the system principal.
+     */
+    [infallible] readonly attribute boolean isSystemPrincipal;
+
     /**
      * Returns true if this principal's origin is recognized as being on the
      * whitelist of sites that can use the CSS Unprefixing Service.
diff --git a/caps/nsNullPrincipal.cpp b/caps/nsNullPrincipal.cpp
index 6f31aae5f45..6c06f7b9402 100644
--- a/caps/nsNullPrincipal.cpp
+++ b/caps/nsNullPrincipal.cpp
@@ -124,13 +124,6 @@ nsNullPrincipal::MayLoadInternal(nsIURI* aURI)
   return false;
 }
 
-NS_IMETHODIMP
-nsNullPrincipal::GetIsNullPrincipal(bool* aIsNullPrincipal)
-{
-  *aIsNullPrincipal = true;
-  return NS_OK;
-}
-
 NS_IMETHODIMP
 nsNullPrincipal::GetBaseDomain(nsACString& aBaseDomain)
 {
diff --git a/caps/nsNullPrincipal.h b/caps/nsNullPrincipal.h
index f2852ba7d20..04c7b0590bd 100644
--- a/caps/nsNullPrincipal.h
+++ b/caps/nsNullPrincipal.h
@@ -44,7 +44,6 @@ public:
   NS_IMETHOD GetURI(nsIURI** aURI) override;
   NS_IMETHOD GetDomain(nsIURI** aDomain) override;
   NS_IMETHOD SetDomain(nsIURI* aDomain) override;
-  NS_IMETHOD GetIsNullPrincipal(bool* aIsNullPrincipal) override;
   NS_IMETHOD GetBaseDomain(nsACString& aBaseDomain) override;
   nsresult GetOriginInternal(nsACString& aOrigin) override;
 
@@ -59,6 +58,8 @@ public:
 
   virtual void GetScriptLocation(nsACString &aStr) override;
 
+  PrincipalKind Kind() override { return eNullPrincipal; }
+
  protected:
   virtual ~nsNullPrincipal() {}
 
diff --git a/caps/nsPrincipal.h b/caps/nsPrincipal.h
index 1c436062905..0c5075bfd1c 100644
--- a/caps/nsPrincipal.h
+++ b/caps/nsPrincipal.h
@@ -49,6 +49,8 @@ public:
    */
   static void InitializeStatics();
 
+  PrincipalKind Kind() override { return eCodebasePrincipal; }
+
   nsCOMPtr<nsIURI> mDomain;
   nsCOMPtr<nsIURI> mCodebase;
   // If mCodebaseImmutable is true, mCodebase is non-null and immutable
@@ -83,6 +85,8 @@ public:
   virtual void GetScriptLocation(nsACString &aStr) override;
   nsresult GetOriginInternal(nsACString& aOrigin) override;
 
+  PrincipalKind Kind() override { return eExpandedPrincipal; }
+
 protected:
   virtual ~nsExpandedPrincipal();
 
diff --git a/caps/nsSystemPrincipal.h b/caps/nsSystemPrincipal.h
index 06c456226c1..5542d09898b 100644
--- a/caps/nsSystemPrincipal.h
+++ b/caps/nsSystemPrincipal.h
@@ -50,6 +50,8 @@ protected:
   {
     return true;
   }
+
+  PrincipalKind Kind() override { return eSystemPrincipal; }
 };
 
 #endif // nsSystemPrincipal_h__
diff --git a/caps/tests/unit/test_origin.js b/caps/tests/unit/test_origin.js
index 30b9e367d25..8bd4d505849 100644
--- a/caps/tests/unit/test_origin.js
+++ b/caps/tests/unit/test_origin.js
@@ -162,4 +162,16 @@ function run_test() {
   checkCrossOrigin(exampleOrg_signedPkg, exampleOrg);
   checkCrossOrigin(exampleOrg_signedPkg, exampleOrg_signedPkg_browser);
   checkCrossOrigin(exampleOrg_signedPkg, exampleOrg_signedPkg_another);
+
+  // Check Principal kinds.
+  function checkKind(prin, kind) {
+    do_check_eq(prin.isNullPrincipal, kind == 'nullPrincipal');
+    do_check_eq(prin.isCodebasePrincipal, kind == 'codebasePrincipal');
+    do_check_eq(prin.isExpandedPrincipal, kind == 'expandedPrincipal');
+    do_check_eq(prin.isSystemPrincipal, kind == 'systemPrincipal');
+  }
+  checkKind(ssm.createNullPrincipal({}), 'nullPrincipal');
+  checkKind(ssm.createCodebasePrincipal(makeURI('http://www.example.com'), {}), 'codebasePrincipal');
+  checkKind(ssm.createExpandedPrincipal([ssm.createCodebasePrincipal(makeURI('http://www.example.com'), {})]), 'expandedPrincipal');
+  checkKind(ssm.getSystemPrincipal(), 'systemPrincipal');
 }
diff --git a/chrome/moz.build b/chrome/moz.build
index 2ba1c2ce39c..c4ee0f64f5f 100644
--- a/chrome/moz.build
+++ b/chrome/moz.build
@@ -33,6 +33,7 @@ GENERATED_INCLUDES += [
 ]
 
 LOCAL_INCLUDES += [
+    '/dom/base',
     '/netwerk/base',
     '/netwerk/protocol/res',
     '/xpcom/components'
diff --git a/chrome/nsChromeRegistry.cpp b/chrome/nsChromeRegistry.cpp
index 378ebb48193..88dc67d3ac9 100644
--- a/chrome/nsChromeRegistry.cpp
+++ b/chrome/nsChromeRegistry.cpp
@@ -313,15 +313,10 @@ nsChromeRegistry::ConvertChromeURL(nsIURI* aChromeURI, nsIURI* *aResult)
 // theme stuff
 
 
-static void FlushSkinBindingsForWindow(nsIDOMWindow* aWindow)
+static void FlushSkinBindingsForWindow(nsPIDOMWindow* aWindow)
 {
-  // Get the DOM document.
-  nsCOMPtr<nsIDOMDocument> domDocument;
-  aWindow->GetDocument(getter_AddRefs(domDocument));
-  if (!domDocument)
-    return;
-
-  nsCOMPtr<nsIDocument> document = do_QueryInterface(domDocument);
+  // Get the document.
+  nsCOMPtr<nsIDocument> document = aWindow->GetDoc();
   if (!document)
     return;
 
@@ -345,7 +340,7 @@ NS_IMETHODIMP nsChromeRegistry::RefreshSkins()
     nsCOMPtr<nsISupports> protoWindow;
     windowEnumerator->GetNext(getter_AddRefs(protoWindow));
     if (protoWindow) {
-      nsCOMPtr<nsIDOMWindow> domWindow = do_QueryInterface(protoWindow);
+      nsCOMPtr<nsPIDOMWindow> domWindow = do_QueryInterface(protoWindow);
       if (domWindow)
         FlushSkinBindingsForWindow(domWindow);
     }
@@ -360,7 +355,7 @@ NS_IMETHODIMP nsChromeRegistry::RefreshSkins()
     nsCOMPtr<nsISupports> protoWindow;
     windowEnumerator->GetNext(getter_AddRefs(protoWindow));
     if (protoWindow) {
-      nsCOMPtr<nsIDOMWindow> domWindow = do_QueryInterface(protoWindow);
+      nsCOMPtr<nsPIDOMWindow> domWindow = do_QueryInterface(protoWindow);
       if (domWindow)
         RefreshWindow(domWindow);
     }
@@ -382,28 +377,23 @@ nsChromeRegistry::FlushSkinCaches()
 }
 
 // XXXbsmedberg: move this to windowmediator
-nsresult nsChromeRegistry::RefreshWindow(nsIDOMWindow* aWindow)
+nsresult nsChromeRegistry::RefreshWindow(nsPIDOMWindow* aWindow)
 {
   // Deal with our subframes first.
-  nsCOMPtr<nsIDOMWindowCollection> frames;
-  aWindow->GetFrames(getter_AddRefs(frames));
+  nsCOMPtr<nsIDOMWindowCollection> frames = aWindow->GetFrames();
   uint32_t length;
   frames->GetLength(&length);
   uint32_t j;
   for (j = 0; j < length; j++) {
     nsCOMPtr<nsIDOMWindow> childWin;
     frames->Item(j, getter_AddRefs(childWin));
-    RefreshWindow(childWin);
+    nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(childWin);
+    RefreshWindow(piWindow);
   }
 
   nsresult rv;
-  // Get the DOM document.
-  nsCOMPtr<nsIDOMDocument> domDocument;
-  aWindow->GetDocument(getter_AddRefs(domDocument));
-  if (!domDocument)
-    return NS_OK;
-
-  nsCOMPtr<nsIDocument> document = do_QueryInterface(domDocument);
+  // Get the document.
+  nsCOMPtr<nsIDocument> document = aWindow->GetDoc();
   if (!document)
     return NS_OK;
 
@@ -521,10 +511,9 @@ nsChromeRegistry::ReloadChrome()
         nsCOMPtr<nsISupports> protoWindow;
         rv = windowEnumerator->GetNext(getter_AddRefs(protoWindow));
         if (NS_SUCCEEDED(rv)) {
-          nsCOMPtr<nsIDOMWindow> domWindow = do_QueryInterface(protoWindow);
+          nsCOMPtr<nsPIDOMWindow> domWindow = do_QueryInterface(protoWindow);
           if (domWindow) {
-            nsCOMPtr<nsIDOMLocation> location;
-            domWindow->GetLocation(getter_AddRefs(location));
+            nsIDOMLocation* location = domWindow->GetLocation();
             if (location) {
               rv = location->Reload(false);
               if (NS_FAILED(rv)) return rv;
diff --git a/chrome/nsChromeRegistry.h b/chrome/nsChromeRegistry.h
index 22fc983d28b..c9176cb3e2d 100644
--- a/chrome/nsChromeRegistry.h
+++ b/chrome/nsChromeRegistry.h
@@ -22,7 +22,7 @@
 
 #include "mozilla/FileLocation.h"
 
-class nsIDOMWindow;
+class nsPIDOMWindow;
 class nsIPrefBranch;
 class nsIURL;
 
@@ -95,7 +95,7 @@ protected:
 
   nsresult SelectLocaleFromPref(nsIPrefBranch* prefs);
 
-  static nsresult RefreshWindow(nsIDOMWindow* aWindow);
+  static nsresult RefreshWindow(nsPIDOMWindow* aWindow);
   static nsresult GetProviderAndPath(nsIURL* aChromeURL,
                                      nsACString& aProvider, nsACString& aPath);
 
diff --git a/devtools/client/tilt/tilt-utils.js b/devtools/client/tilt/tilt-utils.js
index 1208dccf867..bde8a53abda 100644
--- a/devtools/client/tilt/tilt-utils.js
+++ b/devtools/client/tilt/tilt-utils.js
@@ -371,8 +371,10 @@ TiltUtils.DOM = {
     aContentWindow)
   {
     return {
-      width: aContentWindow.innerWidth + aContentWindow.scrollMaxX,
-      height: aContentWindow.innerHeight + aContentWindow.scrollMaxY
+      width: aContentWindow.innerWidth +
+        aContentWindow.scrollMaxX - aContentWindow.scrollMinX,
+      height: aContentWindow.innerHeight +
+        aContentWindow.scrollMaxY - aContentWindow.scrollMinY
     };
   },
 
diff --git a/devtools/shared/gcli/commands/screenshot.js b/devtools/shared/gcli/commands/screenshot.js
index 2155eceac49..be7610e491c 100644
--- a/devtools/shared/gcli/commands/screenshot.js
+++ b/devtools/shared/gcli/commands/screenshot.js
@@ -270,8 +270,8 @@ function createScreenshotData(document, args) {
     // Bug 961832: GCLI screenshot shows fixed position element in wrong
     // position if we don't scroll to top
     window.scrollTo(0,0);
-    width = window.innerWidth + window.scrollMaxX;
-    height = window.innerHeight + window.scrollMaxY;
+    width = window.innerWidth + window.scrollMaxX - window.scrollMinX;
+    height = window.innerHeight + window.scrollMaxY - window.scrollMinY;
   }
   else if (args.selector) {
     ({ top, left, width, height } = getRect(window, args.selector, window));
diff --git a/docshell/base/nsDSURIContentListener.cpp b/docshell/base/nsDSURIContentListener.cpp
index ab86756cc94..98de0eef053 100644
--- a/docshell/base/nsDSURIContentListener.cpp
+++ b/docshell/base/nsDSURIContentListener.cpp
@@ -148,8 +148,8 @@ nsDSURIContentListener::DoContent(const nsACString& aContentType,
   }
 
   if (loadFlags & nsIChannel::LOAD_RETARGETED_DOCUMENT_URI) {
-    nsCOMPtr<nsIDOMWindow> domWindow =
-      mDocShell ? mDocShell->GetWindow() : nullptr;
+    nsCOMPtr<nsPIDOMWindow> domWindow = do_QueryInterface(
+      mDocShell ? mDocShell->GetWindow() : nullptr);
     NS_ENSURE_TRUE(domWindow, NS_ERROR_FAILURE);
     domWindow->Focus();
   }
@@ -294,7 +294,7 @@ nsDSURIContentListener::CheckOneFrameOptionsPolicy(nsIHttpChannel* aHttpChannel,
   // window, if we're not the top.  X-F-O: SAMEORIGIN requires that the
   // document must be same-origin with top window.  X-F-O: DENY requires that
   // the document must never be framed.
-  nsCOMPtr<nsIDOMWindow> thisWindow = mDocShell->GetWindow();
+  nsCOMPtr<nsPIDOMWindow> thisWindow = mDocShell->GetWindow();
   // If we don't have DOMWindow there is no risk of clickjacking
   if (!thisWindow) {
     return true;
@@ -302,8 +302,7 @@ nsDSURIContentListener::CheckOneFrameOptionsPolicy(nsIHttpChannel* aHttpChannel,
 
   // GetScriptableTop, not GetTop, because we want this to respect
   // <iframe mozbrowser> boundaries.
-  nsCOMPtr<nsIDOMWindow> topWindow;
-  thisWindow->GetScriptableTop(getter_AddRefs(topWindow));
+  nsCOMPtr<nsPIDOMWindow> topWindow = thisWindow->GetScriptableTop();
 
   // if the document is in the top window, it's not in a frame.
   if (thisWindow == topWindow) {
diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 61d3c711c91..3c437baf703 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -3503,14 +3503,13 @@ nsDocShell::CanAccessItem(nsIDocShellTreeItem* aTargetItem,
     return false;
   }
 
-  nsCOMPtr<nsIDOMWindow> targetWindow = aTargetItem->GetWindow();
+  nsCOMPtr<nsPIDOMWindow> targetWindow = aTargetItem->GetWindow();
   if (!targetWindow) {
     NS_ERROR("This should not happen, really");
     return false;
   }
 
-  nsCOMPtr<nsIDOMWindow> targetOpener;
-  targetWindow->GetOpener(getter_AddRefs(targetOpener));
+  nsCOMPtr<nsIDOMWindow> targetOpener = targetWindow->GetOpener();
   nsCOMPtr<nsIWebNavigation> openerWebNav(do_GetInterface(targetOpener));
   nsCOMPtr<nsIDocShellTreeItem> openerItem(do_QueryInterface(openerWebNav));
 
@@ -7490,7 +7489,7 @@ nsDocShell::EndPageLoad(nsIWebProgress* aProgress,
         return NS_OK;
       }
 
-      thisWindow->GetFrameElement(getter_AddRefs(frameElement));
+      frameElement = thisWindow->GetFrameElement();
       if (!frameElement) {
         return NS_OK;
       }
@@ -9739,8 +9738,7 @@ nsDocShell::InternalLoad(nsIURI* aURI,
           // So, the best we can do, is to tear down the new window
           // that was just created!
           //
-          nsCOMPtr<nsIDOMWindow> domWin = targetDocShell->GetWindow();
-          if (domWin) {
+          if (nsCOMPtr<nsPIDOMWindow> domWin = targetDocShell->GetWindow()) {
             domWin->Close();
           }
         }
@@ -13006,10 +13004,11 @@ nsDocShell::GetAssociatedWindow(nsIDOMWindow** aWindow)
 NS_IMETHODIMP
 nsDocShell::GetTopWindow(nsIDOMWindow** aWindow)
 {
-  nsCOMPtr<nsIDOMWindow> win = GetWindow();
+  nsCOMPtr<nsPIDOMWindow> win = GetWindow();
   if (win) {
-    win->GetTop(aWindow);
+    win = win->GetTop();
   }
+  win.forget(aWindow);
   return NS_OK;
 }
 
@@ -13017,23 +13016,19 @@ NS_IMETHODIMP
 nsDocShell::GetTopFrameElement(nsIDOMElement** aElement)
 {
   *aElement = nullptr;
-  nsCOMPtr<nsIDOMWindow> win = GetWindow();
+  nsCOMPtr<nsPIDOMWindow> win = GetWindow();
   if (!win) {
     return NS_OK;
   }
 
-  nsCOMPtr<nsIDOMWindow> top;
-  win->GetScriptableTop(getter_AddRefs(top));
+  nsCOMPtr<nsPIDOMWindow> top = win->GetScriptableTop();
   NS_ENSURE_TRUE(top, NS_ERROR_FAILURE);
 
-  nsCOMPtr<nsPIDOMWindow> piTop = do_QueryInterface(top);
-  NS_ENSURE_TRUE(piTop, NS_ERROR_FAILURE);
-
   // GetFrameElementInternal, /not/ GetScriptableFrameElement -- if |top| is
   // inside <iframe mozbrowser>, we want to return the iframe, not null.
   // And we want to cross the content/chrome boundary.
   nsCOMPtr<nsIDOMElement> elt =
-    do_QueryInterface(piTop->GetFrameElementInternal());
+    do_QueryInterface(top->GetFrameElementInternal());
   elt.forget(aElement);
   return NS_OK;
 }
diff --git a/docshell/base/nsDocShellEditorData.cpp b/docshell/base/nsDocShellEditorData.cpp
index 66a510edfb8..c0d06809d20 100644
--- a/docshell/base/nsDocShellEditorData.cpp
+++ b/docshell/base/nsDocShellEditorData.cpp
@@ -158,9 +158,9 @@ nsDocShellEditorData::DetachFromWindow()
   mDetachedMakeEditable = mMakeEditable;
   mMakeEditable = false;
 
-  nsCOMPtr<nsIDOMDocument> domDoc;
-  domWindow->GetDocument(getter_AddRefs(domDoc));
-  nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(domDoc);
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(domWindow);
+  nsCOMPtr<nsIDocument> doc = window->GetDoc();
+  nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(doc);
   if (htmlDoc) {
     mDetachedEditingState = htmlDoc->GetEditingState();
   }
@@ -183,9 +183,9 @@ nsDocShellEditorData::ReattachToWindow(nsIDocShell* aDocShell)
   mIsDetached = false;
   mMakeEditable = mDetachedMakeEditable;
 
-  nsCOMPtr<nsIDOMDocument> domDoc;
-  domWindow->GetDocument(getter_AddRefs(domDoc));
-  nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(domDoc);
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(domWindow);
+  nsCOMPtr<nsIDocument> doc = window->GetDoc();
+  nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(doc);
   if (htmlDoc) {
     htmlDoc->SetEditingState(mDetachedEditingState);
   }
diff --git a/dom/audiochannel/AudioChannelAgent.cpp b/dom/audiochannel/AudioChannelAgent.cpp
index 825268857e3..e2789044ac8 100644
--- a/dom/audiochannel/AudioChannelAgent.cpp
+++ b/dom/audiochannel/AudioChannelAgent.cpp
@@ -112,8 +112,7 @@ AudioChannelAgent::InitInternal(nsIDOMWindow* aWindow, int32_t aChannelType,
   MOZ_ASSERT(pInnerWindow->IsInnerWindow());
   mInnerWindowID = pInnerWindow->WindowID();
 
-  nsCOMPtr<nsIDOMWindow> topWindow;
-  aWindow->GetScriptableTop(getter_AddRefs(topWindow));
+  nsCOMPtr<nsPIDOMWindow> topWindow = pInnerWindow->GetScriptableTop();
   if (NS_WARN_IF(!topWindow)) {
     return NS_OK;
   }
diff --git a/dom/audiochannel/AudioChannelService.cpp b/dom/audiochannel/AudioChannelService.cpp
index d1aaf0bf267..8bdca7bc492 100644
--- a/dom/audiochannel/AudioChannelService.cpp
+++ b/dom/audiochannel/AudioChannelService.cpp
@@ -97,18 +97,16 @@ NotifyChannelActive(uint64_t aWindowID, AudioChannel aAudioChannel,
 }
 
 already_AddRefed<nsPIDOMWindow>
-GetTopWindow(nsIDOMWindow* aWindow)
+GetTopWindow(nsPIDOMWindow* aWindow)
 {
   MOZ_ASSERT(aWindow);
 
-  nsCOMPtr<nsIDOMWindow> topWindow;
-  aWindow->GetScriptableTop(getter_AddRefs(topWindow));
+  nsCOMPtr<nsPIDOMWindow> topWindow = aWindow->GetScriptableTop();
   MOZ_ASSERT(topWindow);
 
-  nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(topWindow);
-  window = window->GetOuterWindow();
+  topWindow = topWindow->GetOuterWindow();
 
-  return window.forget();
+  return topWindow.forget();
 }
 
 bool
@@ -347,8 +345,7 @@ AudioChannelService::GetState(nsPIDOMWindow* aWindow, uint32_t aAudioChannel,
     *aVolume *= window->GetAudioVolume();
     *aMuted = *aMuted || window->GetAudioMuted();
 
-    nsCOMPtr<nsIDOMWindow> win;
-    window->GetScriptableParent(getter_AddRefs(win));
+    nsCOMPtr<nsPIDOMWindow> win = window->GetScriptableParent();
     if (window == win) {
       break;
     }
@@ -540,14 +537,12 @@ AudioChannelService::RefreshAgentsVolume(nsPIDOMWindow* aWindow)
   MOZ_ASSERT(aWindow);
   MOZ_ASSERT(aWindow->IsOuterWindow());
 
-  nsCOMPtr<nsIDOMWindow> topWindow;
-  aWindow->GetScriptableTop(getter_AddRefs(topWindow));
-  nsCOMPtr<nsPIDOMWindow> pTopWindow = do_QueryInterface(topWindow);
-  if (!pTopWindow) {
+  nsCOMPtr<nsPIDOMWindow> topWindow = aWindow->GetScriptableTop();
+  if (!topWindow) {
     return;
   }
 
-  AudioChannelWindow* winData = GetWindowData(pTopWindow->WindowID());
+  AudioChannelWindow* winData = GetWindowData(topWindow->WindowID());
   if (!winData) {
     return;
   }
@@ -566,14 +561,12 @@ AudioChannelService::RefreshAgentsCapture(nsPIDOMWindow* aWindow,
   MOZ_ASSERT(aWindow);
   MOZ_ASSERT(aWindow->IsOuterWindow());
 
-  nsCOMPtr<nsIDOMWindow> topWindow;
-  aWindow->GetScriptableTop(getter_AddRefs(topWindow));
-  nsCOMPtr<nsPIDOMWindow> pTopWindow = do_QueryInterface(topWindow);
-  if (!pTopWindow) {
+  nsCOMPtr<nsPIDOMWindow> topWindow = aWindow->GetScriptableTop();
+  if (!topWindow) {
     return;
   }
 
-  AudioChannelWindow* winData = GetWindowData(pTopWindow->WindowID());
+  AudioChannelWindow* winData = GetWindowData(topWindow->WindowID());
 
   // This can happen, but only during shutdown, because the the outer window
   // changes ScriptableTop, so that its ID is different.
@@ -707,7 +700,8 @@ AudioChannelService::GetAudioChannelVolume(nsIDOMWindow* aWindow,
 {
   MOZ_ASSERT(NS_IsMainThread());
 
-  nsCOMPtr<nsPIDOMWindow> window = GetTopWindow(aWindow);
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(aWindow);
+  nsCOMPtr<nsPIDOMWindow> window = GetTopWindow(piWindow);
   MOZ_ASSERT(window->IsOuterWindow());
   *aVolume = GetAudioChannelVolume(window, (AudioChannel)aAudioChannel);
   return NS_OK;
@@ -734,7 +728,8 @@ AudioChannelService::SetAudioChannelVolume(nsIDOMWindow* aWindow,
 {
   MOZ_ASSERT(NS_IsMainThread());
 
-  nsCOMPtr<nsPIDOMWindow> window = GetTopWindow(aWindow);
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(aWindow);
+  nsCOMPtr<nsPIDOMWindow> window = GetTopWindow(piWindow);
   MOZ_ASSERT(window->IsOuterWindow());
   SetAudioChannelVolume(window, (AudioChannel)aAudioChannel, aVolume);
   return NS_OK;
@@ -759,7 +754,8 @@ AudioChannelService::GetAudioChannelMuted(nsIDOMWindow* aWindow,
 {
   MOZ_ASSERT(NS_IsMainThread());
 
-  nsCOMPtr<nsPIDOMWindow> window = GetTopWindow(aWindow);
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(aWindow);
+  nsCOMPtr<nsPIDOMWindow> window = GetTopWindow(piWindow);
   MOZ_ASSERT(window->IsOuterWindow());
   *aMuted = GetAudioChannelMuted(window, (AudioChannel)aAudioChannel);
   return NS_OK;
@@ -791,7 +787,8 @@ AudioChannelService::SetAudioChannelMuted(nsIDOMWindow* aWindow,
 {
   MOZ_ASSERT(NS_IsMainThread());
 
-  nsCOMPtr<nsPIDOMWindow> window = GetTopWindow(aWindow);
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(aWindow);
+  nsCOMPtr<nsPIDOMWindow> window = GetTopWindow(piWindow);
   MOZ_ASSERT(window->IsOuterWindow());
   SetAudioChannelMuted(window, (AudioChannel)aAudioChannel, aMuted);
   return NS_OK;
@@ -816,7 +813,8 @@ AudioChannelService::IsAudioChannelActive(nsIDOMWindow* aWindow,
 {
   MOZ_ASSERT(NS_IsMainThread());
 
-  nsCOMPtr<nsPIDOMWindow> window = GetTopWindow(aWindow);
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(aWindow);
+  nsCOMPtr<nsPIDOMWindow> window = GetTopWindow(piWindow);
   MOZ_ASSERT(window->IsOuterWindow());
   *aActive = IsAudioChannelActive(window, (AudioChannel)aAudioChannel);
   return NS_OK;
diff --git a/dom/base/Element.h b/dom/base/Element.h
index 6d8f7db42d8..3872c63679c 100644
--- a/dom/base/Element.h
+++ b/dom/base/Element.h
@@ -777,6 +777,12 @@ public:
   {
     return nsPresContext::AppUnitsToIntCSSPixels(GetClientAreaRect().height);
   }
+  int32_t ScrollTopMin()
+  {
+    nsIScrollableFrame* sf = GetScrollFrame();
+    return sf ?
+           nsPresContext::AppUnitsToIntCSSPixels(sf->GetScrollRange().y) : 0;
+  }
   int32_t ScrollTopMax()
   {
     nsIScrollableFrame* sf = GetScrollFrame();
@@ -784,6 +790,12 @@ public:
            nsPresContext::AppUnitsToIntCSSPixels(sf->GetScrollRange().YMost()) :
            0;
   }
+  int32_t ScrollLeftMin()
+  {
+    nsIScrollableFrame* sf = GetScrollFrame();
+    return sf ?
+           nsPresContext::AppUnitsToIntCSSPixels(sf->GetScrollRange().x) : 0;
+  }
   int32_t ScrollLeftMax()
   {
     nsIScrollableFrame* sf = GetScrollFrame();
diff --git a/dom/base/Navigator.cpp b/dom/base/Navigator.cpp
index 2274826a2a2..04e833a1eb3 100644
--- a/dom/base/Navigator.cpp
+++ b/dom/base/Navigator.cpp
@@ -2645,12 +2645,8 @@ Navigator::HasPresentationSupport(JSContext* aCx, JSObject* aGlobal)
     return false;
   }
 
-  nsCOMPtr<nsIDOMWindow> top;
-  nsresult rv = win->GetTop(getter_AddRefs(top));
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return false;
-  }
-
+  win = win->GetOuterWindow();
+  nsCOMPtr<nsPIDOMWindow> top = win->GetTop();
   nsCOMPtr<nsIScriptObjectPrincipal> sop = do_QueryInterface(win);
   nsCOMPtr<nsIScriptObjectPrincipal> topSop = do_QueryInterface(top);
   if (!sop || !topSop) {
@@ -2663,8 +2659,7 @@ Navigator::HasPresentationSupport(JSContext* aCx, JSObject* aGlobal)
     return false;
   }
 
-  nsCOMPtr<nsPIDOMWindow> piTop = do_QueryInterface(top);
-  if (!piTop || !(piTop = piTop->GetCurrentInnerWindow())) {
+  if (!(top = top->GetCurrentInnerWindow())) {
     return false;
   }
 
@@ -2675,7 +2670,7 @@ Navigator::HasPresentationSupport(JSContext* aCx, JSObject* aGlobal)
   }
 
   nsAutoString sessionId;
-  presentationService->GetExistentSessionIdAtLaunch(piTop->WindowID(), sessionId);
+  presentationService->GetExistentSessionIdAtLaunch(top->WindowID(), sessionId);
   return !sessionId.IsEmpty();
 }
 
@@ -2851,53 +2846,96 @@ Navigator::GetUserAgent(nsPIDOMWindow* aWindow, nsIURI* aURI,
 }
 
 #ifdef MOZ_EME
+static nsCString
+ToCString(const nsString& aString)
+{
+  return NS_ConvertUTF16toUTF8(aString);
+}
+
+static nsCString
+ToCString(const MediaKeySystemMediaCapability& aValue)
+{
+  nsCString str;
+  str.AppendLiteral("{contentType='");
+  if (!aValue.mContentType.IsEmpty()) {
+    str.Append(ToCString(aValue.mContentType));
+  }
+  str.AppendLiteral("'}");
+  return str;
+}
+
+template<class Type>
+static nsCString
+ToCString(const Sequence<Type>& aSequence)
+{
+  nsCString s;
+  s.AppendLiteral("[");
+  for (size_t i = 0; i < aSequence.Length(); i++) {
+    if (i != 0) {
+      s.AppendLiteral(",");
+    }
+    s.Append(ToCString(aSequence[i]));
+  }
+  s.AppendLiteral("]");
+  return s;
+}
+
+static nsCString
+ToCString(const MediaKeySystemConfiguration& aConfig)
+{
+  nsCString str;
+  str.AppendLiteral("{");
+  str.AppendPrintf("label='%s'", NS_ConvertUTF16toUTF8(aConfig.mLabel).get());
+
+  if (aConfig.mInitDataTypes.WasPassed()) {
+    str.AppendLiteral(", initDataTypes=");
+    str.Append(ToCString(aConfig.mInitDataTypes.Value()));
+  }
+
+  if (aConfig.mAudioCapabilities.WasPassed()) {
+    str.AppendLiteral(", audioCapabilities=");
+    str.Append(ToCString(aConfig.mAudioCapabilities.Value()));
+  }
+  if (aConfig.mVideoCapabilities.WasPassed()) {
+    str.AppendLiteral(", videoCapabilities=");
+    str.Append(ToCString(aConfig.mVideoCapabilities.Value()));
+  }
+
+  if (!aConfig.mAudioType.IsEmpty()) {
+    str.AppendPrintf(", audioType='%s'",
+      NS_ConvertUTF16toUTF8(aConfig.mAudioType).get());
+  }
+  if (!aConfig.mInitDataType.IsEmpty()) {
+    str.AppendPrintf(", initDataType='%s'",
+      NS_ConvertUTF16toUTF8(aConfig.mInitDataType).get());
+  }
+  if (!aConfig.mVideoType.IsEmpty()) {
+    str.AppendPrintf(", videoType='%s'",
+      NS_ConvertUTF16toUTF8(aConfig.mVideoType).get());
+  }
+  str.AppendLiteral("}");
+
+  return str;
+}
+
+static nsCString
+RequestKeySystemAccessLogString(const nsAString& aKeySystem,
+                                const Sequence<MediaKeySystemConfiguration>& aConfigs)
+{
+  nsCString str;
+  str.AppendPrintf("Navigator::RequestMediaKeySystemAccess(keySystem='%s' options=",
+                   NS_ConvertUTF16toUTF8(aKeySystem).get());
+  str.Append(ToCString(aConfigs));
+  str.AppendLiteral(")");
+  return str;
+}
+
 already_AddRefed<Promise>
 Navigator::RequestMediaKeySystemAccess(const nsAString& aKeySystem,
-                                       const Optional<Sequence<MediaKeySystemOptions>>& aOptions,
+                                       const Sequence<MediaKeySystemConfiguration>& aConfigs,
                                        ErrorResult& aRv)
 {
-  nsAutoCString logMsg;
-  logMsg.AppendPrintf("Navigator::RequestMediaKeySystemAccess(keySystem='%s' options=[",
-                      NS_ConvertUTF16toUTF8(aKeySystem).get());
-  if (aOptions.WasPassed()) {
-    const Sequence<MediaKeySystemOptions>& options = aOptions.Value();
-    for (size_t i = 0; i < options.Length(); i++) {
-      const MediaKeySystemOptions& op = options[i];
-      if (i > 0) {
-        logMsg.AppendLiteral(",");
-      }
-      logMsg.AppendLiteral("{");
-      logMsg.AppendPrintf("stateful='%s'",
-        MediaKeysRequirementValues::strings[(size_t)op.mStateful].value);
-
-      logMsg.AppendPrintf(", uniqueIdentifier='%s'",
-        MediaKeysRequirementValues::strings[(size_t)op.mUniqueidentifier].value);
-
-      if (!op.mAudioCapability.IsEmpty()) {
-        logMsg.AppendPrintf(", audioCapability='%s'",
-                            NS_ConvertUTF16toUTF8(op.mAudioCapability).get());
-      }
-      if (!op.mAudioType.IsEmpty()) {
-        logMsg.AppendPrintf(", audioType='%s'",
-          NS_ConvertUTF16toUTF8(op.mAudioType).get());
-      }
-      if (!op.mInitDataType.IsEmpty()) {
-        logMsg.AppendPrintf(", initDataType='%s'",
-          NS_ConvertUTF16toUTF8(op.mInitDataType).get());
-      }
-      if (!op.mVideoCapability.IsEmpty()) {
-        logMsg.AppendPrintf(", videoCapability='%s'",
-          NS_ConvertUTF16toUTF8(op.mVideoCapability).get());
-      }
-      if (!op.mVideoType.IsEmpty()) {
-        logMsg.AppendPrintf(", videoType='%s'",
-          NS_ConvertUTF16toUTF8(op.mVideoType).get());
-      }
-      logMsg.AppendLiteral("}");
-    }
-  }
-  logMsg.AppendPrintf("])");
-  EME_LOG(logMsg.get());
+  EME_LOG("%s", RequestKeySystemAccessLogString(aKeySystem, aConfigs).get());
 
   nsCOMPtr<nsIGlobalObject> go = do_QueryInterface(mWindow);
   RefPtr<DetailedPromise> promise =
@@ -2913,10 +2951,9 @@ Navigator::RequestMediaKeySystemAccess(const nsAString& aKeySystem,
     mMediaKeySystemAccessManager = new MediaKeySystemAccessManager(mWindow);
   }
 
-  mMediaKeySystemAccessManager->Request(promise, aKeySystem, aOptions);
+  mMediaKeySystemAccessManager->Request(promise, aKeySystem, aConfigs);
   return promise.forget();
 }
-
 #endif
 
 Presentation*
diff --git a/dom/base/Navigator.h b/dom/base/Navigator.h
index 0df73ebea12..b6c592f1f23 100644
--- a/dom/base/Navigator.h
+++ b/dom/base/Navigator.h
@@ -353,7 +353,7 @@ public:
 #ifdef MOZ_EME
   already_AddRefed<Promise>
   RequestMediaKeySystemAccess(const nsAString& aKeySystem,
-                              const Optional<Sequence<MediaKeySystemOptions>>& aOptions,
+                              const Sequence<MediaKeySystemConfiguration>& aConfig,
                               ErrorResult& aRv);
 private:
   RefPtr<MediaKeySystemAccessManager> mMediaKeySystemAccessManager;
diff --git a/dom/base/ThirdPartyUtil.cpp b/dom/base/ThirdPartyUtil.cpp
index 592cfb214c6..e1e6f7e5c2d 100644
--- a/dom/base/ThirdPartyUtil.cpp
+++ b/dom/base/ThirdPartyUtil.cpp
@@ -141,14 +141,12 @@ ThirdPartyUtil::IsThirdPartyWindow(nsIDOMWindow* aWindow,
     }
   }
 
-  nsCOMPtr<nsIDOMWindow> current = aWindow, parent;
+  nsCOMPtr<nsPIDOMWindow> current = do_QueryInterface(aWindow), parent;
   nsCOMPtr<nsIURI> parentURI;
   do {
     // We use GetScriptableParent rather than GetParent because we consider
     // <iframe mozbrowser/mozapp> to be a top-level frame.
-    rv = current->GetScriptableParent(getter_AddRefs(parent));
-    NS_ENSURE_SUCCESS(rv, rv);
-
+    parent = current->GetScriptableParent();
     if (SameCOMIdentity(parent, current)) {
       // We're at the topmost content window. We already know the answer.
       *aResult = false;
@@ -275,9 +273,12 @@ ThirdPartyUtil::IsThirdPartyChannel(nsIChannel* aChannel,
   ctx->GetAssociatedWindow(getter_AddRefs(ourWin));
   if (!ourWin) return NS_ERROR_INVALID_ARG;
 
+  nsCOMPtr<nsPIDOMWindow> piOurWin = do_QueryInterface(ourWin);
+  MOZ_ASSERT(piOurWin);
+
   // We use GetScriptableParent rather than GetParent because we consider
   // <iframe mozbrowser/mozapp> to be a top-level frame.
-  ourWin->GetScriptableParent(getter_AddRefs(parentWin));
+  parentWin = piOurWin->GetScriptableParent();
   NS_ENSURE_TRUE(parentWin, NS_ERROR_INVALID_ARG);
 
   // Check whether this is the document channel for this window (representing a
@@ -315,7 +316,6 @@ ThirdPartyUtil::GetTopWindowForChannel(nsIChannel* aChannel, nsIDOMWindow** aWin
 {
   NS_ENSURE_ARG(aWin);
 
-  nsresult rv;
   // Find the associated window and its parent window.
   nsCOMPtr<nsILoadContext> ctx;
   NS_QueryNotificationCallbacks(aChannel, ctx);
@@ -324,13 +324,15 @@ ThirdPartyUtil::GetTopWindowForChannel(nsIChannel* aChannel, nsIDOMWindow** aWin
   }
 
   nsCOMPtr<nsIDOMWindow> window;
-  rv = ctx->GetAssociatedWindow(getter_AddRefs(window));
-  if (!window) {
+  ctx->GetAssociatedWindow(getter_AddRefs(window));
+  nsCOMPtr<nsPIDOMWindow> top = do_QueryInterface(window);
+  if (!top) {
     return NS_ERROR_INVALID_ARG;
   }
-
-  rv = window->GetTop(aWin);
-  return rv;
+  
+  top = top->GetTop();
+  top.forget(aWin);
+  return NS_OK;
 }
 
 // Get the base domain for aHostURI; e.g. for "www.bbc.co.uk", this would be
diff --git a/dom/base/WebSocket.cpp b/dom/base/WebSocket.cpp
index 464e2e18c89..f29159f5140 100644
--- a/dom/base/WebSocket.cpp
+++ b/dom/base/WebSocket.cpp
@@ -1139,16 +1139,20 @@ protected:
       return true;
     }
 
-    uint64_t windowID = 0;
-    nsCOMPtr<nsIDOMWindow> topWindow;
-    aWindow->GetScriptableTop(getter_AddRefs(topWindow));
-    nsCOMPtr<nsPIDOMWindow> pTopWindow = do_QueryInterface(topWindow);
-    if (pTopWindow) {
-      pTopWindow = pTopWindow->GetCurrentInnerWindow();
+    if (aWindow->IsOuterWindow()) {
+      aWindow = aWindow->GetCurrentInnerWindow();
     }
 
-    if (pTopWindow) {
-      windowID = pTopWindow->WindowID();
+    MOZ_ASSERT(aWindow);
+
+    uint64_t windowID = 0;
+    nsCOMPtr<nsPIDOMWindow> topWindow = aWindow->GetScriptableTop();
+    if (topWindow) {
+      topWindow = topWindow->GetCurrentInnerWindow();
+    }
+
+    if (topWindow) {
+      windowID = topWindow->WindowID();
     }
 
     mImpl->AsyncOpen(principal, windowID, mRv);
@@ -1210,6 +1214,8 @@ WebSocket::Constructor(const GlobalObject& aGlobal,
     }
   }
 
+  MOZ_ASSERT_IF(ownerWindow, ownerWindow->IsInnerWindow());
+
   nsTArray<nsString> protocolArray;
 
   for (uint32_t index = 0, len = aProtocols.Length(); index < len; ++index) {
@@ -1323,16 +1329,16 @@ WebSocket::Constructor(const GlobalObject& aGlobal,
   if (NS_IsMainThread()) {
     MOZ_ASSERT(principal);
 
+    nsPIDOMWindow* outerWindow = ownerWindow->GetOuterWindow();
+
     uint64_t windowID = 0;
-    nsCOMPtr<nsIDOMWindow> topWindow;
-    ownerWindow->GetScriptableTop(getter_AddRefs(topWindow));
-    nsCOMPtr<nsPIDOMWindow> pTopWindow = do_QueryInterface(topWindow);
-    if (pTopWindow) {
-      pTopWindow = pTopWindow->GetCurrentInnerWindow();
+    nsCOMPtr<nsPIDOMWindow> topWindow = outerWindow->GetScriptableTop();
+    if (topWindow) {
+      topWindow = topWindow->GetCurrentInnerWindow();
     }
 
-    if (pTopWindow) {
-      windowID = pTopWindow->WindowID();
+    if (topWindow) {
+      windowID = topWindow->WindowID();
     }
 
     webSocket->mImpl->AsyncOpen(principal, windowID, aRv);
diff --git a/dom/base/nsContentAreaDragDrop.cpp b/dom/base/nsContentAreaDragDrop.cpp
index 78ff555e642..e95045290f2 100644
--- a/dom/base/nsContentAreaDragDrop.cpp
+++ b/dom/base/nsContentAreaDragDrop.cpp
@@ -393,7 +393,7 @@ DragDataProducer::Produce(DataTransfer* aDataTransfer,
       return NS_OK;
   }
   else {
-    mWindow->GetSelection(getter_AddRefs(selection));
+    selection = mWindow->GetSelection();
     if (!selection)
       return NS_OK;
 
diff --git a/dom/base/nsContentPolicy.cpp b/dom/base/nsContentPolicy.cpp
index 7f0c8a3a134..946262f1b16 100644
--- a/dom/base/nsContentPolicy.cpp
+++ b/dom/base/nsContentPolicy.cpp
@@ -188,9 +188,8 @@ nsContentPolicy::CheckPolicy(CPMethod          policyMethod,
         MOZ_ASSERT(window->IsOuterWindow());
 
         if (topFrameElement) {
-            nsCOMPtr<nsIDOMWindow> topWindow;
-            window->GetScriptableTop(getter_AddRefs(topWindow));
-            isTopLevel = topWindow == static_cast<nsIDOMWindow*>(window);
+            nsCOMPtr<nsPIDOMWindow> topWindow = window->GetScriptableTop();
+            isTopLevel = topWindow == window;
         } else {
             // If we don't have a top frame element, then requestingContext is
             // part of the top-level XUL document. Presumably it's the <browser>
diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index bebbd851d2f..48b97ce0ad8 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -6913,7 +6913,7 @@ nsContentUtils::GetRootDocument(nsIDocument* aDoc)
 
 /* static */
 bool
-nsContentUtils::IsInPointerLockContext(nsIDOMWindow* aWin)
+nsContentUtils::IsInPointerLockContext(nsPIDOMWindow* aWin)
 {
   if (!aWin) {
     return false;
@@ -6925,11 +6925,8 @@ nsContentUtils::IsInPointerLockContext(nsIDOMWindow* aWin)
     return false;
   }
 
-  nsCOMPtr<nsIDOMWindow> lockTop;
-  pointerLockedDoc->GetWindow()->GetScriptableTop(getter_AddRefs(lockTop));
-
-  nsCOMPtr<nsIDOMWindow> top;
-  aWin->GetScriptableTop(getter_AddRefs(top));
+  nsCOMPtr<nsPIDOMWindow> lockTop = pointerLockedDoc->GetWindow()->GetScriptableTop();
+  nsCOMPtr<nsPIDOMWindow> top = aWin->GetScriptableTop();
 
   return top == lockTop;
 }
diff --git a/dom/base/nsContentUtils.h b/dom/base/nsContentUtils.h
index f11e3509cd0..24919621b99 100644
--- a/dom/base/nsContentUtils.h
+++ b/dom/base/nsContentUtils.h
@@ -2071,7 +2071,7 @@ public:
    * Returns true if aWin and the current pointer lock document
    * have common scriptable top window.
    */
-  static bool IsInPointerLockContext(nsIDOMWindow* aWin);
+  static bool IsInPointerLockContext(nsPIDOMWindow* aWin);
 
   /**
    * Returns the time limit on handling user input before
diff --git a/dom/base/nsDOMWindowUtils.cpp b/dom/base/nsDOMWindowUtils.cpp
index 9ce9eede8a0..de143c829bc 100644
--- a/dom/base/nsDOMWindowUtils.cpp
+++ b/dom/base/nsDOMWindowUtils.cpp
@@ -1994,15 +1994,20 @@ nsDOMWindowUtils::GetVisitedDependentComputedStyle(
   aResult.Truncate();
 
   nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mWindow);
+  nsCOMPtr<Element> element = do_QueryInterface(aElement);
+  NS_ENSURE_STATE(window && element);
+  window = window->GetCurrentInnerWindow();
   NS_ENSURE_STATE(window);
 
   nsCOMPtr<nsIDOMCSSStyleDeclaration> decl;
-  nsresult rv =
-    window->GetComputedStyle(aElement, aPseudoElement, getter_AddRefs(decl));
-  NS_ENSURE_SUCCESS(rv, rv);
+  {
+    ErrorResult rv;
+    decl = window->GetComputedStyle(*element, aPseudoElement, rv);
+    ENSURE_SUCCESS(rv, rv.StealNSResult());
+  }
 
   static_cast<nsComputedDOMStyle*>(decl.get())->SetExposeVisitedStyle(true);
-  rv = decl->GetPropertyValue(aPropertyName, aResult);
+  nsresult rv = decl->GetPropertyValue(aPropertyName, aResult);
   static_cast<nsComputedDOMStyle*>(decl.get())->SetExposeVisitedStyle(false);
 
   return rv;
diff --git a/dom/base/nsDocument.cpp b/dom/base/nsDocument.cpp
index 8f084d05a03..986cb235501 100644
--- a/dom/base/nsDocument.cpp
+++ b/dom/base/nsDocument.cpp
@@ -3275,12 +3275,11 @@ nsIDocument::HasFocus(ErrorResult& rv) const
     return false;
   }
 
-  // Are we an ancestor of the focused DOMWindow?
-  nsCOMPtr<nsIDOMDocument> domDocument;
-  focusedWindow->GetDocument(getter_AddRefs(domDocument));
-  nsCOMPtr<nsIDocument> document = do_QueryInterface(domDocument);
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(focusedWindow);
+  MOZ_ASSERT(piWindow);
 
-  for (nsIDocument* currentDoc = document; currentDoc;
+  // Are we an ancestor of the focused DOMWindow?
+  for (nsIDocument* currentDoc = piWindow->GetDoc(); currentDoc;
        currentDoc = currentDoc->GetParentDocument()) {
     if (currentDoc == this) {
       // Yes, we are an ancestor
@@ -7002,9 +7001,11 @@ nsIDocument::GetLocation() const
     return nullptr;
   }
 
-  nsCOMPtr<nsIDOMLocation> loc;
-  w->GetLocation(getter_AddRefs(loc));
-  return loc.forget().downcast<nsLocation>();
+  nsGlobalWindow* window = static_cast<nsGlobalWindow*>(w.get());
+  ErrorResult dummy;
+  RefPtr<nsLocation> loc = window->GetLocation(dummy);
+  dummy.SuppressException();
+  return loc.forget();
 }
 
 Element*
@@ -11789,9 +11790,7 @@ ShouldApplyFullscreenDirectly(nsIDocument* aDoc,
   } else {
     // If we are in the chrome process, and the window has not been in
     // fullscreen, we certainly need to make that fullscreen first.
-    bool fullscreen;
-    NS_WARN_IF(NS_FAILED(aRootWin->GetFullScreen(&fullscreen)));
-    if (!fullscreen) {
+    if (!aRootWin->GetFullScreen()) {
       return false;
     }
     // The iterator not being at end indicates there is still some
@@ -12493,18 +12492,15 @@ nsDocument::ShouldLockPointer(Element* aElement, Element* aCurrentLock,
     return false;
   }
 
-  nsCOMPtr<nsIDOMWindow> top;
-  ownerWindow->GetScriptableTop(getter_AddRefs(top));
-  nsCOMPtr<nsPIDOMWindow> piTop = do_QueryInterface(top);
-  if (!piTop || !piTop->GetExtantDoc() ||
-      piTop->GetExtantDoc()->Hidden()) {
+  nsCOMPtr<nsPIDOMWindow> top = ownerWindow->GetScriptableTop();
+  if (!top || !top->GetExtantDoc() || top->GetExtantDoc()->Hidden()) {
     NS_WARNING("ShouldLockPointer(): Top document isn't visible.");
     return false;
   }
 
   if (!aNoFocusCheck) {
     mozilla::ErrorResult rv;
-    if (!piTop->GetExtantDoc()->HasFocus(rv)) {
+    if (!top->GetExtantDoc()->HasFocus(rv)) {
       NS_WARNING("ShouldLockPointer(): Top document isn't focused.");
       return false;
     }
@@ -13286,10 +13282,7 @@ nsAutoSyncOperation::nsAutoSyncOperation(nsIDocument* aDoc)
   if (aDoc) {
     nsPIDOMWindow* win = aDoc->GetWindow();
     if (win) {
-      nsCOMPtr<nsIDOMWindow> topWindow;
-      win->GetTop(getter_AddRefs(topWindow));
-      nsCOMPtr<nsPIDOMWindow> top = do_QueryInterface(topWindow);
-      if (top) {
+      if (nsCOMPtr<nsPIDOMWindow> top = win->GetTop()) {
         nsCOMPtr<nsIDocument> doc = top->GetExtantDoc();
         MarkDocumentTreeToBeInSyncOperation(doc, &mDocuments);
       }
diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index fc271b304ac..3d182d71fb2 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -444,9 +444,7 @@ nsGlobalWindow::DOMMinTimeoutValue() const {
       if (mIsClosed) {                                                        \
         return err_rval;                                                      \
       }                                                                       \
-      nsCOMPtr<nsIDOMDocument> doc;                                           \
-      nsresult fwdic_nr = GetDocument(getter_AddRefs(doc));                   \
-      NS_ENSURE_SUCCESS(fwdic_nr, err_rval);                                  \
+      nsCOMPtr<nsIDocument> doc = GetDoc();                                   \
       if (!mInnerWindow) {                                                    \
         return err_rval;                                                      \
       }                                                                       \
@@ -2338,7 +2336,7 @@ CreateNativeGlobalForInner(JSContext* aCx,
 
   nsGlobalWindow *top = nullptr;
   if (aNewInner->GetOuterWindow()) {
-    top = aNewInner->GetTop();
+    top = aNewInner->GetTopInternal();
   }
   JS::CompartmentOptions options;
 
@@ -2852,7 +2850,7 @@ nsGlobalWindow::DispatchDOMWindowCreated()
 void
 nsGlobalWindow::ClearStatus()
 {
-  SetStatus(EmptyString());
+  SetStatusOuter(EmptyString());
 }
 
 void
@@ -2916,11 +2914,9 @@ nsGlobalWindow::SetDocShell(nsIDocShell* aDocShell)
     // window root object that will function as a chrome event
     // handler and receive all events that occur anywhere inside
     // our window.
-    nsCOMPtr<nsIDOMWindow> parentWindow;
-    GetParent(getter_AddRefs(parentWindow));
-    if (parentWindow.get() != static_cast<nsIDOMWindow*>(this)) {
-      nsCOMPtr<nsPIDOMWindow> piWindow(do_QueryInterface(parentWindow));
-      mChromeEventHandler = piWindow->GetChromeEventHandler();
+    nsCOMPtr<nsPIDOMWindow> parentWindow = GetParent();
+    if (parentWindow.get() != static_cast<nsPIDOMWindow*>(this)) {
+      mChromeEventHandler = parentWindow->GetChromeEventHandler();
     }
     else {
       mChromeEventHandler = NS_NewWindowRoot(this);
@@ -3055,7 +3051,7 @@ nsGlobalWindow::UpdateParentTarget()
     TryGetTabChildGlobalAsEventTarget(frameElement);
 
   if (!eventTarget) {
-    nsGlobalWindow* topWin = GetScriptableTop();
+    nsGlobalWindow* topWin = GetScriptableTopInternal();
     if (topWin) {
       frameElement = topWin->GetFrameElementInternal();
       eventTarget = TryGetTabChildGlobalAsEventTarget(frameElement);
@@ -3162,7 +3158,7 @@ nsGlobalWindow::ShouldPromptToBlockDialogs()
 {
   MOZ_ASSERT(IsOuterWindow());
 
-  nsGlobalWindow *topWindow = GetScriptableTop();
+  nsGlobalWindow *topWindow = GetScriptableTopInternal();
   if (!topWindow) {
     NS_ASSERTION(!mDocShell, "ShouldPromptToBlockDialogs() called without a top window?");
     return true;
@@ -3181,7 +3177,7 @@ nsGlobalWindow::AreDialogsEnabled()
 {
   MOZ_ASSERT(IsOuterWindow());
 
-  nsGlobalWindow *topWindow = GetScriptableTop();
+  nsGlobalWindow *topWindow = GetScriptableTopInternal();
   if (!topWindow) {
     NS_ERROR("AreDialogsEnabled() called without a top window?");
     return false;
@@ -3212,8 +3208,8 @@ bool
 nsGlobalWindow::DialogsAreBeingAbused()
 {
   MOZ_ASSERT(IsInnerWindow());
-  NS_ASSERTION(GetScriptableTop() &&
-               GetScriptableTop()->GetCurrentInnerWindowInternal() == this,
+  NS_ASSERTION(GetScriptableTopInternal() &&
+               GetScriptableTopInternal()->GetCurrentInnerWindowInternal() == this,
                "DialogsAreBeingAbused called with invalid window");
 
   if (mLastDialogQuitTime.IsNull() ||
@@ -3273,7 +3269,7 @@ nsGlobalWindow::ConfirmDialogIfNeeded()
 void
 nsGlobalWindow::DisableDialogs()
 {
-  nsGlobalWindow *topWindow = GetScriptableTop();
+  nsGlobalWindow *topWindow = GetScriptableTopInternal();
   if (!topWindow) {
     NS_ERROR("DisableDialogs() called without a top window?");
     return;
@@ -3289,7 +3285,7 @@ nsGlobalWindow::DisableDialogs()
 void
 nsGlobalWindow::EnableDialogs()
 {
-  nsGlobalWindow *topWindow = GetScriptableTop();
+  nsGlobalWindow *topWindow = GetScriptableTopInternal();
   if (!topWindow) {
     NS_ERROR("EnableDialogs() called without a top window?");
     return;
@@ -3566,48 +3562,18 @@ nsPIDOMWindow::UnmuteAudioContexts()
   }
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetDocument(nsIDOMDocument** aDocument)
-{
-  nsCOMPtr<nsIDOMDocument> document = do_QueryInterface(GetDocument());
-  document.forget(aDocument);
-  return NS_OK;
-}
-
 nsGlobalWindow*
 nsGlobalWindow::Window()
 {
   return this;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetWindow(nsIDOMWindow** aWindow)
-{
-  FORWARD_TO_OUTER(GetWindow, (aWindow), NS_ERROR_UNEXPECTED);
-
-  nsCOMPtr<nsIDOMWindow> window = Window();
-  window.forget(aWindow);
-
-  return NS_OK;
-}
-
 nsGlobalWindow*
 nsGlobalWindow::Self()
 {
   return this;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetSelf(nsIDOMWindow** aWindow)
-{
-  FORWARD_TO_OUTER(GetSelf, (aWindow), NS_ERROR_UNEXPECTED);
-
-  nsCOMPtr<nsIDOMWindow> window = Self();
-  window.forget(aWindow);
-
-  return NS_OK;
-}
-
 Navigator*
 nsGlobalWindow::GetNavigator(ErrorResult& aError)
 {
@@ -3620,16 +3586,15 @@ nsGlobalWindow::GetNavigator(ErrorResult& aError)
   return mNavigator;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetNavigator(nsIDOMNavigator** aNavigator)
+nsIDOMNavigator*
+nsGlobalWindow::GetNavigator()
 {
-  FORWARD_TO_INNER(GetNavigator, (aNavigator), NS_ERROR_UNEXPECTED);
+  FORWARD_TO_INNER(GetNavigator, (), nullptr);
 
-  ErrorResult rv;
-  nsCOMPtr<nsIDOMNavigator> navigator = GetNavigator(rv);
-  navigator.forget(aNavigator);
-
-  return rv.StealNSResult();
+  ErrorResult dummy;
+  nsIDOMNavigator* navigator = GetNavigator(dummy);
+  dummy.SuppressException();
+  return navigator;
 }
 
 nsScreen*
@@ -3648,16 +3613,15 @@ nsGlobalWindow::GetScreen(ErrorResult& aError)
   return mScreen;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetScreen(nsIDOMScreen** aScreen)
+nsIDOMScreen*
+nsGlobalWindow::GetScreen()
 {
-  FORWARD_TO_INNER(GetScreen, (aScreen), NS_ERROR_UNEXPECTED);
+  FORWARD_TO_INNER(GetScreen, (), nullptr);
 
-  ErrorResult rv;
-  RefPtr<nsScreen> screen = GetScreen(rv);
-  screen.forget(aScreen);
-
-  return rv.StealNSResult();
+  ErrorResult dummy;
+  nsIDOMScreen* screen = GetScreen(dummy);
+  dummy.SuppressException();
+  return screen;
 }
 
 nsHistory*
@@ -3672,18 +3636,6 @@ nsGlobalWindow::GetHistory(ErrorResult& aError)
   return mHistory;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetHistory(nsISupports** aHistory)
-{
-  FORWARD_TO_INNER(GetHistory, (aHistory), NS_ERROR_FAILURE);
-
-  ErrorResult rv;
-  nsCOMPtr<nsISupports> history = GetHistory(rv);
-  history.forget(aHistory);
-
-  return rv.StealNSResult();
-}
-
 nsPerformance*
 nsPIDOMWindow::GetPerformance()
 {
@@ -3712,15 +3664,13 @@ nsPIDOMWindow::CreatePerformanceObjectIfNeeded()
     // If we are dealing with an iframe, we will need the parent's performance
     // object (so we can add the iframe as a resource of that page).
     nsPerformance* parentPerformance = nullptr;
-    nsCOMPtr<nsIDOMWindow> parentWindow;
-    GetScriptableParent(getter_AddRefs(parentWindow));
-    nsCOMPtr<nsPIDOMWindow> parentPWindow = do_GetInterface(parentWindow);
-    if (GetOuterWindow() != parentPWindow) {
-      if (parentPWindow && !parentPWindow->IsInnerWindow()) {
-        parentPWindow = parentPWindow->GetCurrentInnerWindow();
+    nsCOMPtr<nsPIDOMWindow> parentWindow = GetScriptableParent();
+    if (GetOuterWindow() != parentWindow) {
+      if (parentWindow && !parentWindow->IsInnerWindow()) {
+        parentWindow = parentWindow->GetCurrentInnerWindow();
       }
-      if (parentPWindow) {
-        parentPerformance = parentPWindow->GetPerformance();
+      if (parentWindow) {
+        parentPerformance = parentWindow->GetPerformance();
       }
     }
     mPerformance =
@@ -3828,7 +3778,7 @@ nsGlobalWindow::GetSpeechSynthesis(ErrorResult& aError)
 #endif
 
 already_AddRefed<nsIDOMWindow>
-nsGlobalWindow::GetParentOuter(ErrorResult& aError)
+nsGlobalWindow::GetParentOuter()
 {
   MOZ_RELEASE_ASSERT(IsOuterWindow());
 
@@ -3840,7 +3790,7 @@ nsGlobalWindow::GetParentOuter(ErrorResult& aError)
   if (mDocShell->GetIsBrowserOrApp()) {
     parent = this;
   } else {
-    aError = GetRealParent(getter_AddRefs(parent));
+    parent = GetParent();
   }
 
   return parent.forget();
@@ -3849,7 +3799,7 @@ nsGlobalWindow::GetParentOuter(ErrorResult& aError)
 already_AddRefed<nsIDOMWindow>
 nsGlobalWindow::GetParent(ErrorResult& aError)
 {
-  FORWARD_TO_OUTER_OR_THROW(GetParentOuter, (aError), aError, nullptr);
+  FORWARD_TO_OUTER_OR_THROW(GetParentOuter, (), aError, nullptr);
 }
 
 /**
@@ -3859,30 +3809,27 @@ nsGlobalWindow::GetParent(ErrorResult& aError)
  * mozbrowser> boundaries, so if |this| is contained by an <iframe
  * mozbrowser>, we will return |this| as its own parent.
  */
-NS_IMETHODIMP
-nsGlobalWindow::GetScriptableParent(nsIDOMWindow** aParent)
+nsPIDOMWindow*
+nsGlobalWindow::GetScriptableParent()
 {
-  FORWARD_TO_OUTER(GetScriptableParent, (aParent), NS_ERROR_UNEXPECTED);
+  FORWARD_TO_OUTER(GetScriptableParent, (), nullptr);
 
-  ErrorResult rv;
-  nsCOMPtr<nsIDOMWindow> parent = GetParentOuter(rv);
-  parent.forget(aParent);
-
-  return rv.StealNSResult();
+  nsCOMPtr<nsIDOMWindow> parent = GetParentOuter();
+  nsCOMPtr<nsPIDOMWindow> piParent = do_QueryInterface(parent);
+  return piParent.get();
 }
 
 /**
- * nsIDOMWindow::GetParent (when called from C++) is just a wrapper around
+ * nsPIDOMWindow::GetParent (when called from C++) is just a wrapper around
  * GetRealParent.
  */
-NS_IMETHODIMP
-nsGlobalWindow::GetRealParent(nsIDOMWindow** aParent)
+already_AddRefed<nsPIDOMWindow>
+nsGlobalWindow::GetParent()
 {
-  FORWARD_TO_OUTER(GetRealParent, (aParent), NS_ERROR_NOT_INITIALIZED);
+  MOZ_ASSERT(IsOuterWindow());
 
-  *aParent = nullptr;
   if (!mDocShell) {
-    return NS_OK;
+    return nullptr;
   }
 
   nsCOMPtr<nsIDocShell> parent;
@@ -3890,24 +3837,22 @@ nsGlobalWindow::GetRealParent(nsIDOMWindow** aParent)
 
   if (parent) {
     nsCOMPtr<nsPIDOMWindow> win = parent->GetWindow();
-    win.forget(aParent);
+    return win.forget();
   }
-  else {
-    *aParent = static_cast<nsIDOMWindow*>(this);
-    NS_ADDREF(*aParent);
-  }
-  return NS_OK;
+
+  nsCOMPtr<nsPIDOMWindow> win(this);
+  return win.forget();
 }
 
 static nsresult
-GetTopImpl(nsGlobalWindow* aWin, nsIDOMWindow** aTop, bool aScriptable)
+GetTopImpl(nsGlobalWindow* aWin, nsPIDOMWindow** aTop, bool aScriptable)
 {
   *aTop = nullptr;
 
   // Walk up the parent chain.
 
-  nsCOMPtr<nsIDOMWindow> prevParent = aWin;
-  nsCOMPtr<nsIDOMWindow> parent = aWin;
+  nsCOMPtr<nsPIDOMWindow> prevParent = aWin;
+  nsCOMPtr<nsPIDOMWindow> parent = aWin;
   do {
     if (!parent) {
       break;
@@ -3915,15 +3860,13 @@ GetTopImpl(nsGlobalWindow* aWin, nsIDOMWindow** aTop, bool aScriptable)
 
     prevParent = parent;
 
-    nsCOMPtr<nsIDOMWindow> newParent;
-    nsresult rv;
+    nsCOMPtr<nsPIDOMWindow> newParent;
     if (aScriptable) {
-      rv = parent->GetScriptableParent(getter_AddRefs(newParent));
+      newParent = parent->GetScriptableParent();
     }
     else {
-      rv = parent->GetParent(getter_AddRefs(newParent));
+      newParent = parent->GetParent();
     }
-    NS_ENSURE_SUCCESS(rv, rv);
 
     parent = newParent;
 
@@ -3943,30 +3886,22 @@ GetTopImpl(nsGlobalWindow* aWin, nsIDOMWindow** aTop, bool aScriptable)
  * boundaries.  If we encounter a window owned by an <iframe mozbrowser> while
  * walking up the window hierarchy, we'll stop and return that window.
  */
-NS_IMETHODIMP
-nsGlobalWindow::GetScriptableTop(nsIDOMWindow **aTop)
+nsPIDOMWindow*
+nsGlobalWindow::GetScriptableTop()
 {
-  FORWARD_TO_OUTER(GetScriptableTop, (aTop), NS_ERROR_NOT_INITIALIZED);
-  return GetTopImpl(this, aTop, /* aScriptable = */ true);
+  FORWARD_TO_OUTER(GetScriptableTop, (), nullptr);
+  nsCOMPtr<nsPIDOMWindow> window;
+  GetTopImpl(this, getter_AddRefs(window), /* aScriptable = */ true);
+  return window.get();
 }
 
-/**
- * nsIDOMWindow::GetTop (when called from C++) is just a wrapper around
- * GetRealTop.
- */
-NS_IMETHODIMP
-nsGlobalWindow::GetRealTop(nsIDOMWindow** aTop)
+already_AddRefed<nsPIDOMWindow>
+nsGlobalWindow::GetTop()
 {
-  nsGlobalWindow* outer;
-  if (IsInnerWindow()) {
-    outer = GetOuterWindowInternal();
-    if (!outer) {
-      return NS_ERROR_NOT_INITIALIZED;
-    }
-  } else {
-    outer = this;
-  }
-  return GetTopImpl(outer, aTop, /* aScriptable = */ false);
+  MOZ_ASSERT(IsOuterWindow());
+  nsCOMPtr<nsPIDOMWindow> window;
+  GetTopImpl(this, getter_AddRefs(window), /* aScriptable = */ false);
+  return window.forget();
 }
 
 void
@@ -4019,7 +3954,7 @@ nsGlobalWindow::GetContentInternal(ErrorResult& aError, bool aUnprivilegedCaller
   // If we're contained in <iframe mozbrowser> or <iframe mozapp>, then
   // GetContent is the same as window.top.
   if (mDocShell && mDocShell->GetIsInBrowserOrApp()) {
-    return GetTopOuter(aError);
+    return GetTopOuter();
   }
 
   nsCOMPtr<nsIDocShellTreeItem> primaryContent;
@@ -4086,7 +4021,7 @@ nsGlobalWindow::GetScriptableContent(JSContext* aCx, JS::MutableHandle<JS::Value
   return rv.StealNSResult();
 }
 
-NS_IMETHODIMP
+nsresult
 nsGlobalWindow::GetPrompter(nsIPrompt** aPrompt)
 {
   if (IsInnerWindow()) {
@@ -4120,18 +4055,6 @@ nsGlobalWindow::GetMenubar(ErrorResult& aError)
   return mMenubar;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetMenubar(nsISupports** aMenubar)
-{
-  FORWARD_TO_INNER(GetMenubar, (aMenubar), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  nsCOMPtr<nsISupports> menubar = GetMenubar(rv);
-  menubar.forget(aMenubar);
-
-  return rv.StealNSResult();
-}
-
 BarProp*
 nsGlobalWindow::GetToolbar(ErrorResult& aError)
 {
@@ -4144,18 +4067,6 @@ nsGlobalWindow::GetToolbar(ErrorResult& aError)
   return mToolbar;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetToolbar(nsISupports** aToolbar)
-{
-  FORWARD_TO_INNER(GetToolbar, (aToolbar), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  nsCOMPtr<nsISupports> toolbar = GetToolbar(rv);
-  toolbar.forget(aToolbar);
-
-  return rv.StealNSResult();
-}
-
 BarProp*
 nsGlobalWindow::GetLocationbar(ErrorResult& aError)
 {
@@ -4167,18 +4078,6 @@ nsGlobalWindow::GetLocationbar(ErrorResult& aError)
   return mLocationbar;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetLocationbar(nsISupports** aLocationbar)
-{
-  FORWARD_TO_INNER(GetLocationbar, (aLocationbar), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  nsCOMPtr<nsISupports> locationbar = GetLocationbar(rv);
-  locationbar.forget(aLocationbar);
-
-  return rv.StealNSResult();
-}
-
 BarProp*
 nsGlobalWindow::GetPersonalbar(ErrorResult& aError)
 {
@@ -4190,18 +4089,6 @@ nsGlobalWindow::GetPersonalbar(ErrorResult& aError)
   return mPersonalbar;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetPersonalbar(nsISupports** aPersonalbar)
-{
-  FORWARD_TO_INNER(GetPersonalbar, (aPersonalbar), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  nsCOMPtr<nsISupports> personalbar = GetPersonalbar(rv);
-  personalbar.forget(aPersonalbar);
-
-  return rv.StealNSResult();
-}
-
 BarProp*
 nsGlobalWindow::GetStatusbar(ErrorResult& aError)
 {
@@ -4213,18 +4100,6 @@ nsGlobalWindow::GetStatusbar(ErrorResult& aError)
   return mStatusbar;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetStatusbar(nsISupports** aStatusbar)
-{
-  FORWARD_TO_INNER(GetStatusbar, (aStatusbar), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  nsCOMPtr<nsISupports> statusbar = GetStatusbar(rv);
-  statusbar.forget(aStatusbar);
-
-  return rv.StealNSResult();
-}
-
 BarProp*
 nsGlobalWindow::GetScrollbars(ErrorResult& aError)
 {
@@ -4237,18 +4112,6 @@ nsGlobalWindow::GetScrollbars(ErrorResult& aError)
   return mScrollbars;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetScrollbars(nsISupports** aScrollbars)
-{
-  FORWARD_TO_INNER(GetScrollbars, (aScrollbars), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  nsCOMPtr<nsISupports> scrollbars = GetScrollbars(rv);
-  scrollbars.forget(aScrollbars);
-
-  return rv.StealNSResult();
-}
-
 bool
 nsGlobalWindow::GetClosedOuter()
 {
@@ -4264,15 +4127,12 @@ nsGlobalWindow::GetClosed(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetClosedOuter, (), aError, false);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetClosed(bool* aClosed)
+bool
+nsGlobalWindow::Closed()
 {
-  FORWARD_TO_INNER(GetClosed, (aClosed), NS_ERROR_UNEXPECTED);
+  MOZ_ASSERT(IsOuterWindow());
 
-  ErrorResult rv;
-  *aClosed = GetClosed(rv);
-
-  return rv.StealNSResult();
+  return GetClosedOuter();
 }
 
 nsDOMWindowList*
@@ -4287,14 +4147,13 @@ nsGlobalWindow::GetWindowList()
   return mFrames;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetFrames(nsIDOMWindowCollection** aFrames)
+already_AddRefed<nsIDOMWindowCollection>
+nsGlobalWindow::GetFrames()
 {
-  FORWARD_TO_OUTER(GetFrames, (aFrames), NS_ERROR_NOT_INITIALIZED);
+  FORWARD_TO_OUTER(GetFrames, (), nullptr);
 
-  *aFrames = GetWindowList();
-  NS_IF_ADDREF(*aFrames);
-  return NS_OK;
+  nsCOMPtr<nsIDOMWindowCollection> frames = GetWindowList();
+  return frames.forget();
 }
 
 already_AddRefed<nsIDOMWindow>
@@ -4470,17 +4329,16 @@ nsGlobalWindow::GetApplicationCache(ErrorResult& aError)
   return mApplicationCache;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetApplicationCache(nsIDOMOfflineResourceList **aApplicationCache)
+already_AddRefed<nsIDOMOfflineResourceList>
+nsGlobalWindow::GetApplicationCache()
 {
-  FORWARD_TO_INNER(GetApplicationCache, (aApplicationCache), NS_ERROR_UNEXPECTED);
+  FORWARD_TO_INNER(GetApplicationCache, (), nullptr);
 
-  ErrorResult rv;
+  ErrorResult dummy;
   nsCOMPtr<nsIDOMOfflineResourceList> applicationCache =
-    GetApplicationCache(rv);
-  applicationCache.forget(aApplicationCache);
-
-  return rv.StealNSResult();
+    GetApplicationCache(dummy);
+  dummy.SuppressException();
+  return applicationCache.forget();
 }
 
 Crypto*
@@ -4495,18 +4353,6 @@ nsGlobalWindow::GetCrypto(ErrorResult& aError)
   return mCrypto;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetCrypto(nsIDOMCrypto** aCrypto)
-{
-  FORWARD_TO_INNER(GetCrypto, (aCrypto), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  nsCOMPtr<nsIDOMCrypto> crypto = GetCrypto(rv);
-  crypto.forget(aCrypto);
-
-  return rv.StealNSResult();
-}
-
 nsIControllers*
 nsGlobalWindow::GetControllersOuter(ErrorResult& aError)
 {
@@ -4547,7 +4393,7 @@ nsGlobalWindow::GetControllers(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetControllersOuter, (aError), aError, nullptr);
 }
 
-NS_IMETHODIMP
+nsresult
 nsGlobalWindow::GetControllers(nsIControllers** aResult)
 {
   FORWARD_TO_INNER(GetControllers, (aResult), NS_ERROR_UNEXPECTED);
@@ -4559,7 +4405,7 @@ nsGlobalWindow::GetControllers(nsIControllers** aResult)
   return rv.StealNSResult();
 }
 
-nsIDOMWindow*
+nsPIDOMWindow*
 nsGlobalWindow::GetOpenerWindowOuter()
 {
   MOZ_RELEASE_ASSERT(IsOuterWindow());
@@ -4607,7 +4453,7 @@ nsGlobalWindow::GetOpenerWindowOuter()
   return nullptr;
 }
 
-nsIDOMWindow*
+nsPIDOMWindow*
 nsGlobalWindow::GetOpenerWindow(ErrorResult& aError)
 {
   FORWARD_TO_OUTER_OR_THROW(GetOpenerWindowOuter, (), aError, nullptr);
@@ -4619,7 +4465,7 @@ nsGlobalWindow::GetOpener(JSContext* aCx, JS::MutableHandle<JS::Value> aRetval,
 {
   MOZ_ASSERT(IsInnerWindow());
 
-  nsCOMPtr<nsIDOMWindow> opener = GetOpenerWindow(aError);
+  nsCOMPtr<nsPIDOMWindow> opener = GetOpenerWindow(aError);
   if (aError.Failed() || !opener) {
     aRetval.setNull();
     return;
@@ -4628,27 +4474,15 @@ nsGlobalWindow::GetOpener(JSContext* aCx, JS::MutableHandle<JS::Value> aRetval,
   aError = nsContentUtils::WrapNative(aCx, opener, aRetval);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetScriptableOpener(JSContext* aCx,
-                                    JS::MutableHandle<JS::Value> aOpener)
+already_AddRefed<nsPIDOMWindow>
+nsGlobalWindow::GetOpener()
 {
-  FORWARD_TO_INNER(GetScriptableOpener, (aCx, aOpener), NS_ERROR_UNEXPECTED);
+  FORWARD_TO_INNER(GetOpener, (), nullptr);
 
-  ErrorResult rv;
-  GetOpener(aCx, aOpener, rv);
-
-  return rv.StealNSResult();
-}
-
-NS_IMETHODIMP
-nsGlobalWindow::GetOpener(nsIDOMWindow** aOpener)
-{
-  FORWARD_TO_INNER(GetOpener, (aOpener), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  nsCOMPtr<nsIDOMWindow> opener = GetOpenerWindow(rv);
-  opener.forget(aOpener);
-  return rv.StealNSResult();
+  ErrorResult dummy;
+  nsCOMPtr<nsPIDOMWindow> opener = GetOpenerWindow(dummy);
+  dummy.SuppressException();
+  return opener.forget();
 }
 
 void
@@ -4700,23 +4534,6 @@ nsGlobalWindow::SetOpener(JSContext* aCx, JS::Handle<JS::Value> aOpener,
   SetOpenerWindow(win, false);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::SetScriptableOpener(JSContext* aCx,
-                                    JS::Handle<JS::Value> aOpener)
-{
-  ErrorResult rv;
-  SetOpener(aCx, aOpener, rv);
-
-  return rv.StealNSResult();
-}
-
-NS_IMETHODIMP
-nsGlobalWindow::SetOpener(nsIDOMWindow* aOpener)
-{
-  SetOpenerWindow(aOpener, false);
-  return NS_OK;
-}
-
 void
 nsGlobalWindow::GetStatusOuter(nsAString& aStatus)
 {
@@ -4731,17 +4548,6 @@ nsGlobalWindow::GetStatus(nsAString& aStatus, ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetStatusOuter, (aStatus), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetStatus(nsAString& aStatus)
-{
-  FORWARD_TO_INNER(GetStatus, (aStatus), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  GetStatus(aStatus, rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::SetStatusOuter(const nsAString& aStatus)
 {
@@ -4771,17 +4577,6 @@ nsGlobalWindow::SetStatus(const nsAString& aStatus, ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(SetStatusOuter, (aStatus), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::SetStatus(const nsAString& aStatus)
-{
-  FORWARD_TO_INNER(SetStatus, (aStatus), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  SetStatus(aStatus, rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::GetNameOuter(nsAString& aName)
 {
@@ -4798,17 +4593,6 @@ nsGlobalWindow::GetName(nsAString& aName, ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetNameOuter, (aName), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetName(nsAString& aName)
-{
-  FORWARD_TO_INNER(GetName, (aName), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  GetName(aName, rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::SetNameOuter(const nsAString& aName, mozilla::ErrorResult& aError)
 {
@@ -4825,17 +4609,6 @@ nsGlobalWindow::SetName(const nsAString& aName, mozilla::ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(SetNameOuter, (aName, aError), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::SetName(const nsAString& aName)
-{
-  FORWARD_TO_INNER(SetName, (aName), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  SetName(aName, rv);
-
-  return rv.StealNSResult();
-}
-
 // Helper functions used by many methods below.
 int32_t
 nsGlobalWindow::DevToCSSIntPixels(int32_t px)
@@ -4961,7 +4734,7 @@ nsGlobalWindow::GetInnerWidth(JSContext* aCx,
                             aError);
 }
 
-NS_IMETHODIMP
+nsresult
 nsGlobalWindow::GetInnerWidth(int32_t* aInnerWidth)
 {
   FORWARD_TO_INNER(GetInnerWidth, (aInnerWidth), NS_ERROR_UNEXPECTED);
@@ -5022,21 +4795,6 @@ nsGlobalWindow::SetInnerWidth(JSContext* aCx, JS::Handle<JS::Value> aValue,
                             aValue, "innerWidth", aError);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::SetInnerWidth(int32_t aInnerWidth)
-{
-  FORWARD_TO_OUTER(SetInnerWidth, (aInnerWidth), NS_ERROR_UNEXPECTED);
-
-  if (IsFrame()) {
-    return NS_OK;
-  }
-
-  ErrorResult rv;
-  SetInnerWidthOuter(aInnerWidth, rv, /* aCallerIsChrome = */ true);
-
-  return rv.StealNSResult();
-}
-
 int32_t
 nsGlobalWindow::GetInnerHeightOuter(ErrorResult& aError)
 {
@@ -5062,7 +4820,7 @@ nsGlobalWindow::GetInnerHeight(JSContext* aCx,
                             aError);
 }
 
-NS_IMETHODIMP
+nsresult
 nsGlobalWindow::GetInnerHeight(int32_t* aInnerHeight)
 {
   FORWARD_TO_INNER(GetInnerHeight, (aInnerHeight), NS_ERROR_UNEXPECTED);
@@ -5122,21 +4880,6 @@ nsGlobalWindow::SetInnerHeight(JSContext* aCx, JS::Handle<JS::Value> aValue,
                             aValue, "innerHeight", aError);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::SetInnerHeight(int32_t aInnerHeight)
-{
-  FORWARD_TO_OUTER(SetInnerHeight, (aInnerHeight), NS_ERROR_UNEXPECTED);
-
-  if (IsFrame()) {
-    return NS_OK;
-  }
-
-  ErrorResult rv;
-  SetInnerHeightOuter(aInnerHeight, rv, /* aCallerIsChrome = */ true);
-
-  return rv.StealNSResult();
-}
-
 nsIntSize
 nsGlobalWindow::GetOuterSize(ErrorResult& aError)
 {
@@ -5191,17 +4934,6 @@ nsGlobalWindow::GetOuterWidth(JSContext* aCx,
                             aError);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetOuterWidth(int32_t* aOuterWidth)
-{
-  FORWARD_TO_INNER(GetOuterWidth, (aOuterWidth), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  *aOuterWidth = GetOuterWidth(rv);
-
-  return rv.StealNSResult();
-}
-
 int32_t
 nsGlobalWindow::GetOuterHeightOuter(ErrorResult& aError)
 {
@@ -5224,17 +4956,6 @@ nsGlobalWindow::GetOuterHeight(JSContext* aCx,
                             aError);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetOuterHeight(int32_t* aOuterHeight)
-{
-  FORWARD_TO_INNER(GetOuterHeight, (aOuterHeight), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  *aOuterHeight = GetOuterHeight(rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::SetOuterSize(int32_t aLengthCSSPixels, bool aIsWidth,
                              ErrorResult& aError, bool aCallerIsChrome)
@@ -5288,21 +5009,6 @@ nsGlobalWindow::SetOuterWidth(JSContext* aCx, JS::Handle<JS::Value> aValue,
                             aValue, "outerWidth", aError);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::SetOuterWidth(int32_t aOuterWidth)
-{
-  FORWARD_TO_OUTER(SetOuterWidth, (aOuterWidth), NS_ERROR_UNEXPECTED);
-
-  if (IsFrame()) {
-    return NS_OK;
-  }
-
-  ErrorResult rv;
-  SetOuterWidthOuter(aOuterWidth, rv, /* aCallerIsChrome = */ true);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::SetOuterHeightOuter(int32_t aOuterHeight, ErrorResult& aError, bool aCallerIsChrome)
 {
@@ -5325,21 +5031,6 @@ nsGlobalWindow::SetOuterHeight(JSContext* aCx, JS::Handle<JS::Value> aValue,
                             aValue, "outerHeight", aError);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::SetOuterHeight(int32_t aOuterHeight)
-{
-  FORWARD_TO_OUTER(SetOuterHeight, (aOuterHeight), NS_ERROR_UNEXPECTED);
-
-  if (IsFrame()) {
-    return NS_OK;
-  }
-
-  ErrorResult rv;
-  SetOuterHeightOuter(aOuterHeight, rv, /* aCallerIsChrome = */ true);
-
-  return rv.StealNSResult();
-}
-
 nsIntPoint
 nsGlobalWindow::GetScreenXY(ErrorResult& aError)
 {
@@ -5384,17 +5075,6 @@ nsGlobalWindow::GetScreenX(JSContext* aCx,
                             aError);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetScreenX(int32_t* aScreenX)
-{
-  FORWARD_TO_INNER(GetScreenX, (aScreenX), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  *aScreenX = GetScreenX(rv);
-
-  return rv.StealNSResult();
-}
-
 nsRect
 nsGlobalWindow::GetInnerScreenRect()
 {
@@ -5446,17 +5126,6 @@ nsGlobalWindow::GetMozInnerScreenX(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetMozInnerScreenXOuter, (), aError, 0);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetMozInnerScreenX(float* aScreenX)
-{
-  FORWARD_TO_INNER(GetMozInnerScreenX, (aScreenX), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  *aScreenX = GetMozInnerScreenX(rv);
-
-  return rv.StealNSResult();
-}
-
 float
 nsGlobalWindow::GetMozInnerScreenYOuter()
 {
@@ -5477,17 +5146,6 @@ nsGlobalWindow::GetMozInnerScreenY(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetMozInnerScreenYOuter, (), aError, 0);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetMozInnerScreenY(float* aScreenY)
-{
-  FORWARD_TO_INNER(GetMozInnerScreenY, (aScreenY), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  *aScreenY = GetMozInnerScreenY(rv);
-
-  return rv.StealNSResult();
-}
-
 float
 nsGlobalWindow::GetDevicePixelRatioOuter()
 {
@@ -5517,7 +5175,7 @@ nsGlobalWindow::GetDevicePixelRatio(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetDevicePixelRatioOuter, (), aError, 0.0);
 }
 
-NS_IMETHODIMP
+nsresult
 nsGlobalWindow::GetDevicePixelRatio(float* aRatio)
 {
   FORWARD_TO_INNER(GetDevicePixelRatio, (aRatio), NS_ERROR_UNEXPECTED);
@@ -5547,17 +5205,6 @@ nsGlobalWindow::GetMozPaintCount(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetMozPaintCountOuter, (), aError, 0);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetMozPaintCount(uint64_t* aResult)
-{
-  FORWARD_TO_INNER(GetMozPaintCount, (aResult), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  *aResult = GetMozPaintCount(rv);
-
-  return rv.StealNSResult();
-}
-
 int32_t
 nsGlobalWindow::RequestAnimationFrame(FrameRequestCallback& aCallback,
                                       ErrorResult& aError)
@@ -5577,26 +5224,6 @@ nsGlobalWindow::RequestAnimationFrame(FrameRequestCallback& aCallback,
   return handle;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::RequestAnimationFrame(JS::Handle<JS::Value> aCallback,
-                                      JSContext* cx,
-                                      int32_t* aHandle)
-{
-  FORWARD_TO_INNER(RequestAnimationFrame, (aCallback, cx, aHandle), NS_ERROR_UNEXPECTED);
-  if (!aCallback.isObject() || !JS::IsCallable(&aCallback.toObject())) {
-    return NS_ERROR_INVALID_ARG;
-  }
-
-  JS::Rooted<JSObject*> callbackObj(cx, &aCallback.toObject());
-  RefPtr<FrameRequestCallback> callback =
-    new FrameRequestCallback(cx, callbackObj, GetIncumbentGlobal());
-
-  ErrorResult rv;
-  *aHandle = RequestAnimationFrame(*callback, rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::CancelAnimationFrame(int32_t aHandle, ErrorResult& aError)
 {
@@ -5609,17 +5236,6 @@ nsGlobalWindow::CancelAnimationFrame(int32_t aHandle, ErrorResult& aError)
   mDoc->CancelFrameRequestCallback(aHandle);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::CancelAnimationFrame(int32_t aHandle)
-{
-  FORWARD_TO_INNER(CancelAnimationFrame, (aHandle), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  CancelAnimationFrame(aHandle, rv);
-
-  return rv.StealNSResult();
-}
-
 already_AddRefed<MediaQueryList>
 nsGlobalWindow::MatchMediaOuter(const nsAString& aMediaQueryList)
 {
@@ -5643,19 +5259,6 @@ nsGlobalWindow::MatchMedia(const nsAString& aMediaQueryList,
   FORWARD_TO_OUTER_OR_THROW(MatchMediaOuter, (aMediaQueryList), aError, nullptr);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::MatchMedia(const nsAString& aMediaQueryList,
-                           nsISupports** aResult)
-{
-  FORWARD_TO_INNER(MatchMedia, (aMediaQueryList, aResult), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  RefPtr<MediaQueryList> mediaQueryList = MatchMedia(aMediaQueryList, rv);
-  mediaQueryList.forget(aResult);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::SetScreenXOuter(int32_t aScreenX, ErrorResult& aError, bool aCallerIsChrome)
 {
@@ -5693,21 +5296,6 @@ nsGlobalWindow::SetScreenX(JSContext* aCx, JS::Handle<JS::Value> aValue,
                             aValue, "screenX", aError);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::SetScreenX(int32_t aScreenX)
-{
-  FORWARD_TO_OUTER(SetScreenX, (aScreenX), NS_ERROR_UNEXPECTED);
-
-  if (IsFrame()) {
-    return NS_OK;
-  }
-
-  ErrorResult rv;
-  SetScreenXOuter(aScreenX, rv, /* aCallerIsChrome = */ true);
-
-  return rv.StealNSResult();
-}
-
 int32_t
 nsGlobalWindow::GetScreenYOuter(ErrorResult& aError)
 {
@@ -5722,17 +5310,6 @@ nsGlobalWindow::GetScreenY(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetScreenYOuter, (aError), aError, 0);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetScreenY(int32_t* aScreenY)
-{
-  FORWARD_TO_INNER(GetScreenY, (aScreenY), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  *aScreenY = GetScreenY(rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::GetScreenY(JSContext* aCx,
                            JS::MutableHandle<JS::Value> aValue,
@@ -5779,21 +5356,6 @@ nsGlobalWindow::SetScreenY(JSContext* aCx, JS::Handle<JS::Value> aValue,
                             aValue, "screenY", aError);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::SetScreenY(int32_t aScreenY)
-{
-  FORWARD_TO_OUTER(SetScreenY, (aScreenY), NS_ERROR_UNEXPECTED);
-
-  if (IsFrame()) {
-    return NS_OK;
-  }
-
-  ErrorResult rv;
-  SetScreenYOuter(aScreenY, rv, /* aCallerIsChrome = */ true);
-
-  return rv.StealNSResult();
-}
-
 // NOTE: Arguments to this function should have values scaled to
 // CSS pixels, not device pixels.
 void
@@ -5883,8 +5445,7 @@ nsGlobalWindow::CheckSecurityLeftAndTop(int32_t* aLeft, int32_t* aTop, bool aCal
 
     nsCOMPtr<nsIBaseWindow> treeOwner = GetTreeOwnerWindow();
 
-    nsCOMPtr<nsIDOMScreen> screen;
-    GetScreen(getter_AddRefs(screen));
+    nsCOMPtr<nsIDOMScreen> screen = GetScreen();
 
     if (treeOwner && screen) {
       int32_t screenLeft, screenTop, screenWidth, screenHeight;
@@ -5939,91 +5500,44 @@ nsGlobalWindow::CheckSecurityLeftAndTop(int32_t* aLeft, int32_t* aTop, bool aCal
   }
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetPageXOffset(int32_t* aPageXOffset)
-{
-  return GetScrollX(aPageXOffset);
-}
-
-NS_IMETHODIMP
-nsGlobalWindow::GetPageYOffset(int32_t* aPageYOffset)
-{
-  return GetScrollY(aPageYOffset);
-}
-
-void
-nsGlobalWindow::GetScrollMaxXYOuter(int32_t* aScrollMaxX, int32_t* aScrollMaxY)
+int32_t
+nsGlobalWindow::GetScrollBoundaryOuter(Side aSide)
 {
   MOZ_RELEASE_ASSERT(IsOuterWindow());
 
   FlushPendingNotifications(Flush_Layout);
-  nsIScrollableFrame *sf = GetScrollFrame();
-  if (!sf) {
-    return;
-  }
-
-  nsRect scrollRange = sf->GetScrollRange();
-
-  if (aScrollMaxX) {
-    *aScrollMaxX = std::max(0,
-      (int32_t)floor(nsPresContext::AppUnitsToFloatCSSPixels(scrollRange.XMost())));
-  }
-  if (aScrollMaxY) {
-    *aScrollMaxY = std::max(0,
-      (int32_t)floor(nsPresContext::AppUnitsToFloatCSSPixels(scrollRange.YMost())));
+  if (nsIScrollableFrame *sf = GetScrollFrame()) {
+    return sf->GetScrollRange().Edge(aSide);
   }
+  return 0;
 }
 
-void
-nsGlobalWindow::GetScrollMaxXY(int32_t* aScrollMaxX, int32_t* aScrollMaxY,
-                               ErrorResult& aError)
+int32_t
+nsGlobalWindow::GetScrollMinX(ErrorResult& aError)
 {
-  FORWARD_TO_OUTER_OR_THROW(GetScrollMaxXYOuter, (aScrollMaxX, aScrollMaxY),
-                          aError, );
+  MOZ_ASSERT(IsInnerWindow());
+  FORWARD_TO_OUTER_OR_THROW(GetScrollBoundaryOuter, (eSideLeft), aError, 0);
+}
+
+int32_t
+nsGlobalWindow::GetScrollMinY(ErrorResult& aError)
+{
+  MOZ_ASSERT(IsInnerWindow());
+  FORWARD_TO_OUTER_OR_THROW(GetScrollBoundaryOuter, (eSideTop), aError, 0);
 }
 
 int32_t
 nsGlobalWindow::GetScrollMaxX(ErrorResult& aError)
 {
   MOZ_ASSERT(IsInnerWindow());
-
-  int32_t scrollMaxX = 0;
-  GetScrollMaxXY(&scrollMaxX, nullptr, aError);
-  return scrollMaxX;
-}
-
-NS_IMETHODIMP
-nsGlobalWindow::GetScrollMaxX(int32_t* aScrollMaxX)
-{
-  FORWARD_TO_INNER(GetScrollMaxX, (aScrollMaxX), NS_ERROR_UNEXPECTED);
-
-  NS_ENSURE_ARG_POINTER(aScrollMaxX);
-  ErrorResult rv;
-  *aScrollMaxX = GetScrollMaxX(rv);
-
-  return rv.StealNSResult();
+  FORWARD_TO_OUTER_OR_THROW(GetScrollBoundaryOuter, (eSideRight), aError, 0);
 }
 
 int32_t
 nsGlobalWindow::GetScrollMaxY(ErrorResult& aError)
 {
   MOZ_ASSERT(IsInnerWindow());
-
-  int32_t scrollMaxY = 0;
-  GetScrollMaxXY(nullptr, &scrollMaxY, aError);
-  return scrollMaxY;
-}
-
-NS_IMETHODIMP
-nsGlobalWindow::GetScrollMaxY(int32_t* aScrollMaxY)
-{
-  FORWARD_TO_INNER(GetScrollMaxY, (aScrollMaxY), NS_ERROR_UNEXPECTED);
-
-  NS_ENSURE_ARG_POINTER(aScrollMaxY);
-  ErrorResult rv;
-  *aScrollMaxY = GetScrollMaxY(rv);
-
-  return rv.StealNSResult();
+  FORWARD_TO_OUTER_OR_THROW(GetScrollBoundaryOuter, (eSideBottom), aError, 0);
 }
 
 CSSIntPoint
@@ -6066,16 +5580,6 @@ nsGlobalWindow::GetScrollX(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetScrollXOuter, (), aError, 0);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetScrollX(int32_t* aScrollX)
-{
-  FORWARD_TO_INNER(GetScrollX, (aScrollX), NS_ERROR_UNEXPECTED);
-  NS_ENSURE_ARG_POINTER(aScrollX);
-  ErrorResult rv;
-  *aScrollX = GetScrollX(rv);
-  return rv.StealNSResult();
-}
-
 int32_t
 nsGlobalWindow::GetScrollYOuter()
 {
@@ -6089,16 +5593,6 @@ nsGlobalWindow::GetScrollY(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetScrollYOuter, (), aError, 0);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetScrollY(int32_t* aScrollY)
-{
-  FORWARD_TO_INNER(GetScrollY, (aScrollY), NS_ERROR_UNEXPECTED);
-  NS_ENSURE_ARG_POINTER(aScrollY);
-  ErrorResult rv;
-  *aScrollY = GetScrollY(rv);
-  return rv.StealNSResult();
-}
-
 uint32_t
 nsGlobalWindow::Length()
 {
@@ -6109,27 +5603,19 @@ nsGlobalWindow::Length()
   return windows ? windows->GetLength() : 0;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetLength(uint32_t* aLength)
-{
-  *aLength = Length();
-  return NS_OK;
-}
-
 already_AddRefed<nsIDOMWindow>
-nsGlobalWindow::GetTopOuter(mozilla::ErrorResult& aError)
+nsGlobalWindow::GetTopOuter()
 {
   MOZ_ASSERT(IsOuterWindow());
 
-  nsCOMPtr<nsIDOMWindow> top;
-  aError = GetScriptableTop(getter_AddRefs(top));
+  nsCOMPtr<nsPIDOMWindow> top = GetScriptableTop();
   return top.forget();
 }
 
 already_AddRefed<nsIDOMWindow>
 nsGlobalWindow::GetTop(mozilla::ErrorResult& aError)
 {
-  FORWARD_TO_OUTER_OR_THROW(GetTopOuter, (aError), aError, nullptr);
+  FORWARD_TO_OUTER_OR_THROW(GetTopOuter, (), aError, nullptr);
 }
 
 nsPIDOMWindow*
@@ -6285,7 +5771,7 @@ nsGlobalWindow::SetFullScreen(bool aFullScreen, mozilla::ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(SetFullScreenOuter, (aFullScreen, aError), aError, /* void */);
 }
 
-NS_IMETHODIMP
+nsresult
 nsGlobalWindow::SetFullScreen(bool aFullScreen)
 {
   FORWARD_TO_OUTER(SetFullScreen, (aFullScreen), NS_ERROR_NOT_INITIALIZED);
@@ -6618,7 +6104,7 @@ nsGlobalWindow::SetWidgetFullscreen(FullscreenReason aReason, bool aIsFullscreen
                                     nsIWidget* aWidget, nsIScreen* aScreen)
 {
   MOZ_ASSERT(IsOuterWindow());
-  MOZ_ASSERT(this == GetTop(), "Only topmost window should call this");
+  MOZ_ASSERT(this == GetTopInternal(), "Only topmost window should call this");
   MOZ_ASSERT(!GetFrameElementInternal(), "Content window should not call this");
   MOZ_ASSERT(XRE_GetProcessType() == GeckoProcessType_Default);
 
@@ -6732,15 +6218,15 @@ nsGlobalWindow::GetFullScreen(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetFullScreenOuter, (), aError, false);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetFullScreen(bool* aFullScreen)
+bool
+nsGlobalWindow::GetFullScreen()
 {
-  FORWARD_TO_INNER(GetFullScreen, (aFullScreen), NS_ERROR_UNEXPECTED);
+  FORWARD_TO_INNER(GetFullScreen, (), false);
 
-  ErrorResult rv;
-  *aFullScreen = GetFullScreen(rv);
-
-  return rv.StealNSResult();
+  ErrorResult dummy;
+  bool fullscreen = GetFullScreen(dummy);
+  dummy.SuppressException();
+  return fullscreen;
 }
 
 void
@@ -6800,37 +6286,6 @@ nsGlobalWindow::EnsureReflowFlushAndPaint()
   presShell->UnsuppressPainting();
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetTextZoom(float *aZoom)
-{
-  FORWARD_TO_OUTER(GetTextZoom, (aZoom), NS_ERROR_NOT_INITIALIZED);
-
-  if (mDocShell) {
-    nsCOMPtr<nsIContentViewer> contentViewer;
-    mDocShell->GetContentViewer(getter_AddRefs(contentViewer));
-
-    if (contentViewer) {
-      return contentViewer->GetTextZoom(aZoom);
-    }
-  }
-  return NS_ERROR_FAILURE;
-}
-
-NS_IMETHODIMP
-nsGlobalWindow::SetTextZoom(float aZoom)
-{
-  FORWARD_TO_OUTER(SetTextZoom, (aZoom), NS_ERROR_NOT_INITIALIZED);
-
-  if (mDocShell) {
-    nsCOMPtr<nsIContentViewer> contentViewer;
-    mDocShell->GetContentViewer(getter_AddRefs(contentViewer));
-
-    if (contentViewer)
-      return contentViewer->SetTextZoom(aZoom);
-  }
-  return NS_ERROR_FAILURE;
-}
-
 // static
 void
 nsGlobalWindow::MakeScriptDialogTitle(nsAString &aOutTitle)
@@ -7041,17 +6496,6 @@ nsGlobalWindow::Alert(const nsAString& aMessage, mozilla::ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(AlertOuter, (aMessage, aError), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Alert(const nsAString& aString)
-{
-  FORWARD_TO_INNER(Alert, (aString), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  Alert(aString, rv);
-
-  return rv.StealNSResult();
-}
-
 bool
 nsGlobalWindow::ConfirmOuter(const nsAString& aMessage, ErrorResult& aError)
 {
@@ -7066,17 +6510,6 @@ nsGlobalWindow::Confirm(const nsAString& aMessage, ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(ConfirmOuter, (aMessage, aError), aError, false);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Confirm(const nsAString& aString, bool* aReturn)
-{
-  FORWARD_TO_INNER(Confirm, (aString, aReturn), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  *aReturn = Confirm(aString, rv);
-
-  return rv.StealNSResult();
-}
-
 already_AddRefed<Promise>
 nsGlobalWindow::Fetch(const RequestOrUSVString& aInput,
                       const RequestInit& aInit, ErrorResult& aRv)
@@ -7175,18 +6608,6 @@ nsGlobalWindow::Prompt(const nsAString& aMessage, const nsAString& aInitial,
                             aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Prompt(const nsAString& aMessage, const nsAString& aInitial,
-                       nsAString& aReturn)
-{
-  FORWARD_TO_INNER(Prompt, (aMessage, aInitial, aReturn), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  Prompt(aMessage, aInitial, aReturn, rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::FocusOuter(ErrorResult& aError)
 {
@@ -7211,8 +6632,7 @@ nsGlobalWindow::FocusOuter(ErrorResult& aError)
 
   nsCOMPtr<nsPIDOMWindow> caller = do_QueryInterface(GetEntryGlobal());
   caller = caller ? caller->GetOuterWindow() : nullptr;
-  nsCOMPtr<nsIDOMWindow> opener;
-  GetOpener(getter_AddRefs(opener));
+  nsCOMPtr<nsIDOMWindow> opener = GetOpener();
 
   // Enforce dom.disable_window_flip (for non-chrome), but still allow the
   // window which opened us to raise us at times when popups are allowed
@@ -7302,7 +6722,7 @@ nsGlobalWindow::Focus(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(FocusOuter, (aError), aError, );
 }
 
-NS_IMETHODIMP
+nsresult
 nsGlobalWindow::Focus()
 {
   FORWARD_TO_INNER(Focus, (), NS_ERROR_UNEXPECTED);
@@ -7351,15 +6771,6 @@ nsGlobalWindow::Blur(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(BlurOuter, (), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Blur()
-{
-  ErrorResult rv;
-  Blur(rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::BackOuter(ErrorResult& aError)
 {
@@ -7380,17 +6791,6 @@ nsGlobalWindow::Back(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(BackOuter, (aError), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Back()
-{
-  FORWARD_TO_INNER(Back, (), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  Back(rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::ForwardOuter(ErrorResult& aError)
 {
@@ -7411,17 +6811,6 @@ nsGlobalWindow::Forward(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(ForwardOuter, (aError), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Forward()
-{
-  FORWARD_TO_INNER(Forward, (), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  Forward(rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::HomeOuter(ErrorResult& aError)
 {
@@ -7480,17 +6869,6 @@ nsGlobalWindow::Home(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(HomeOuter, (aError), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Home()
-{
-  FORWARD_TO_INNER(Home, (), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  Home(rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::StopOuter(ErrorResult& aError)
 {
@@ -7508,17 +6886,6 @@ nsGlobalWindow::Stop(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(StopOuter, (aError), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Stop()
-{
-  FORWARD_TO_INNER(Stop, (), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  Stop(rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::PrintOuter(ErrorResult& aError)
 {
@@ -7604,17 +6971,6 @@ nsGlobalWindow::Print(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(PrintOuter, (aError), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Print()
-{
-  FORWARD_TO_INNER(Print, (), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  Print(rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::MoveToOuter(int32_t aXPos, int32_t aYPos, ErrorResult& aError, bool aCallerIsChrome)
 {
@@ -7649,17 +7005,6 @@ nsGlobalWindow::MoveTo(int32_t aXPos, int32_t aYPos, ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(MoveToOuter, (aXPos, aYPos, aError, nsContentUtils::IsCallerChrome()), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::MoveTo(int32_t aXPos, int32_t aYPos)
-{
-  FORWARD_TO_OUTER(MoveTo, (aXPos, aYPos), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  MoveToOuter(aXPos, aYPos, rv, /* aCallerIsChrome = */ true);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::MoveByOuter(int32_t aXDif, int32_t aYDif, ErrorResult& aError, bool aCallerIsChrome)
 {
@@ -7709,7 +7054,7 @@ nsGlobalWindow::MoveBy(int32_t aXDif, int32_t aYDif, ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(MoveByOuter, (aXDif, aYDif, aError, nsContentUtils::IsCallerChrome()), aError, );
 }
 
-NS_IMETHODIMP
+nsresult
 nsGlobalWindow::MoveBy(int32_t aXDif, int32_t aYDif)
 {
   FORWARD_TO_OUTER(MoveBy, (aXDif, aYDif), NS_ERROR_UNEXPECTED);
@@ -7767,17 +7112,6 @@ nsGlobalWindow::ResizeTo(int32_t aWidth, int32_t aHeight, ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(ResizeToOuter, (aWidth, aHeight, aError, nsContentUtils::IsCallerChrome()), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::ResizeTo(int32_t aWidth, int32_t aHeight)
-{
-  FORWARD_TO_OUTER(ResizeTo, (aWidth, aHeight), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  ResizeToOuter(aWidth, aHeight, rv, nsContentUtils::IsCallerChrome());
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::ResizeByOuter(int32_t aWidthDif, int32_t aHeightDif,
                               ErrorResult& aError, bool aCallerIsChrome)
@@ -7848,17 +7182,6 @@ nsGlobalWindow::ResizeBy(int32_t aWidthDif, int32_t aHeightDif,
   FORWARD_TO_OUTER_OR_THROW(ResizeByOuter, (aWidthDif, aHeightDif, aError, nsContentUtils::IsCallerChrome()), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::ResizeBy(int32_t aWidthDif, int32_t aHeightDif)
-{
-  FORWARD_TO_OUTER(ResizeBy, (aWidthDif, aHeightDif), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  ResizeByOuter(aWidthDif, aHeightDif, rv, /* aCallerIsChrome = */ true);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::SizeToContentOuter(ErrorResult& aError, bool aCallerIsChrome)
 {
@@ -7915,24 +7238,6 @@ nsGlobalWindow::SizeToContent(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(SizeToContentOuter, (aError, nsContentUtils::IsCallerChrome()), aError, );
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::SizeToContent()
-{
-  FORWARD_TO_OUTER(SizeToContent, (), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  SizeToContentOuter(rv, /* aCallerIsChrome = */ true);
-
-  return rv.StealNSResult();
-}
-
-NS_IMETHODIMP
-nsGlobalWindow::GetWindowRoot(nsIDOMEventTarget **aWindowRoot)
-{
-  nsCOMPtr<nsPIWindowRoot> root = GetTopWindowRoot();
-  return CallQueryInterface(root, aWindowRoot);
-}
-
 already_AddRefed<nsPIWindowRoot>
 nsGlobalWindow::GetTopWindowRoot()
 {
@@ -7988,20 +7293,6 @@ nsGlobalWindow::Scroll(const ScrollToOptions& aOptions)
   ScrollTo(aOptions);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Scroll(int32_t aXScroll, int32_t aYScroll)
-{
-  ScrollTo(CSSIntPoint(aXScroll, aYScroll), ScrollOptions());
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsGlobalWindow::ScrollTo(int32_t aXScroll, int32_t aYScroll)
-{
-  ScrollTo(CSSIntPoint(aXScroll, aYScroll), ScrollOptions());
-  return NS_OK;
-}
-
 void
 nsGlobalWindow::ScrollTo(const CSSIntPoint& aScroll,
                          const ScrollOptions& aOptions)
@@ -8034,14 +7325,6 @@ nsGlobalWindow::ScrollTo(const CSSIntPoint& aScroll,
   }
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::ScrollBy(int32_t aXScrollDif, int32_t aYScrollDif)
-{
-  ScrollBy(double(aXScrollDif), double(aYScrollDif));
-
-  return NS_OK;
-}
-
 void
 nsGlobalWindow::ScrollBy(double aXScrollDif, double aYScrollDif)
 {
@@ -8078,16 +7361,6 @@ nsGlobalWindow::ScrollBy(const ScrollToOptions& aOptions)
   }
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::ScrollByLines(int32_t numLines)
-{
-  FORWARD_TO_INNER(ScrollByLines, (numLines), NS_ERROR_UNEXPECTED);
-
-  ScrollByLines(numLines, ScrollOptions());
-
-  return NS_OK;
-}
-
 void
 nsGlobalWindow::ScrollByLines(int32_t numLines,
                               const ScrollOptions& aOptions)
@@ -8109,16 +7382,6 @@ nsGlobalWindow::ScrollByLines(int32_t numLines,
   }
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::ScrollByPages(int32_t numPages)
-{
-  FORWARD_TO_INNER(ScrollByPages, (numPages), NS_ERROR_UNEXPECTED);
-
-  ScrollByPages(numPages, ScrollOptions());
-
-  return NS_OK;
-}
-
 void
 nsGlobalWindow::ScrollByPages(int32_t numPages,
                               const ScrollOptions& aOptions)
@@ -8286,17 +7549,13 @@ nsGlobalWindow::PopupWhitelisted()
   if (!IsPopupBlocked(mDoc))
     return true;
 
-  nsCOMPtr<nsIDOMWindow> parent;
-
-  if (NS_FAILED(GetParent(getter_AddRefs(parent))) ||
-      parent == static_cast<nsIDOMWindow*>(this))
+  nsCOMPtr<nsPIDOMWindow> parent = GetParent();
+  if (parent == static_cast<nsPIDOMWindow*>(this))
   {
     return false;
   }
 
-  return static_cast<nsGlobalWindow*>
-                    (static_cast<nsIDOMWindow*>
-                                (parent.get()))->PopupWhitelisted();
+  return static_cast<nsGlobalWindow*>(parent.get())->PopupWhitelisted();
 }
 
 /*
@@ -8350,9 +7609,7 @@ nsGlobalWindow::FireAbuseEvents(bool aBlocked, bool aWindow,
 {
   // fetch the URI of the window requesting the opened window
 
-  nsCOMPtr<nsIDOMWindow> topWindow;
-  GetTop(getter_AddRefs(topWindow));
-  nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(topWindow);
+  nsCOMPtr<nsPIDOMWindow> window = GetTop();
   if (!window) {
     return;
   }
@@ -8405,22 +7662,27 @@ nsGlobalWindow::Open(const nsAString& aUrl, const nsAString& aName,
                             nullptr);
 }
 
-NS_IMETHODIMP
+nsresult
 nsGlobalWindow::Open(const nsAString& aUrl, const nsAString& aName,
-                     const nsAString& aOptions, nsIDOMWindow **_retval)
+                     const nsAString& aOptions, nsPIDOMWindow **_retval)
 {
   FORWARD_TO_OUTER(Open, (aUrl, aName, aOptions, _retval),
                    NS_ERROR_NOT_INITIALIZED);
-  return OpenInternal(aUrl, aName, aOptions,
-                      false,          // aDialog
-                      false,          // aContentModal
-                      true,           // aCalledNoScript
-                      false,          // aDoJSFixups
-                      true,           // aNavigate
-                      nullptr, nullptr,  // No args
-                      GetPrincipal(),    // aCalleePrincipal
-                      nullptr,           // aJSCallerContext
-                      _retval);
+  nsCOMPtr<nsIDOMWindow> window;
+  nsresult rv = OpenInternal(aUrl, aName, aOptions,
+                             false,          // aDialog
+                             false,          // aContentModal
+                             true,           // aCalledNoScript
+                             false,          // aDoJSFixups
+                             true,           // aNavigate
+                             nullptr, nullptr,  // No args
+                             GetPrincipal(),    // aCalleePrincipal
+                             nullptr,           // aJSCallerContext
+                             getter_AddRefs(window));
+  if (NS_SUCCEEDED(rv) && window) {
+    return CallQueryInterface(window, _retval);
+  }
+  return rv;
 }
 
 nsresult
@@ -8442,13 +7704,12 @@ nsGlobalWindow::OpenJS(const nsAString& aUrl, const nsAString& aName,
 
 // like Open, but attaches to the new window any extra parameters past
 // [features] as a JS property named "arguments"
-NS_IMETHODIMP
+nsresult
 nsGlobalWindow::OpenDialog(const nsAString& aUrl, const nsAString& aName,
                            const nsAString& aOptions,
                            nsISupports* aExtraArgument, nsIDOMWindow** _retval)
 {
-  FORWARD_TO_OUTER(OpenDialog, (aUrl, aName, aOptions, aExtraArgument, _retval),
-                   NS_ERROR_NOT_INITIALIZED);
+  MOZ_ASSERT(IsOuterWindow());
   return OpenInternal(aUrl, aName, aOptions,
                       true,                    // aDialog
                       false,                   // aContentModal
@@ -8733,22 +7994,6 @@ nsGlobalWindow::PostMessageMoz(JSContext* aCx, JS::Handle<JS::Value> aMessage,
   PostMessageMoz(aCx, aMessage, aTargetOrigin, transferArray, aError);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::PostMessageMoz(JS::Handle<JS::Value> aMessage,
-                               const nsAString& aOrigin,
-                               JS::Handle<JS::Value> aTransfer,
-                               JSContext* aCx)
-{
-  FORWARD_TO_INNER(PostMessageMoz,
-                   (aMessage, aOrigin, aTransfer, aCx),
-                   NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  PostMessageMoz(aCx, aMessage, aOrigin, aTransfer, rv);
-
-  return rv.StealNSResult();
-}
-
 class nsCloseEvent : public nsRunnable {
 
   RefPtr<nsGlobalWindow> mWindow;
@@ -8892,7 +8137,7 @@ nsGlobalWindow::Close(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(CloseOuter, (nsContentUtils::IsCallerChrome()), aError, );
 }
 
-NS_IMETHODIMP
+nsresult
 nsGlobalWindow::Close()
 {
   FORWARD_TO_OUTER(Close, (), NS_ERROR_UNEXPECTED);
@@ -9013,7 +8258,7 @@ nsGlobalWindow::EnterModalState()
 
   // GetScriptableTop, not GetTop, so that EnterModalState works properly with
   // <iframe mozbrowser>.
-  nsGlobalWindow* topWin = GetScriptableTop();
+  nsGlobalWindow* topWin = GetScriptableTopInternal();
 
   if (!topWin) {
     NS_ERROR("Uh, EnterModalState() called w/o a reachable top window?");
@@ -9090,19 +8335,15 @@ nsGlobalWindow::RunPendingTimeoutsRecursive(nsGlobalWindow *aTopWindow,
     return;
   }
 
-  nsCOMPtr<nsIDOMWindowCollection> frames;
-  aWindow->GetFrames(getter_AddRefs(frames));
-
+  nsCOMPtr<nsIDOMWindowCollection> frames = aWindow->GetFrames();
   if (!frames) {
     return;
   }
 
-  uint32_t i, length;
-  if (NS_FAILED(frames->GetLength(&length)) || !length) {
-    return;
-  }
+  uint32_t length = 0;
+  frames->GetLength(&length);
 
-  for (i = 0; i < length && aTopWindow->mModalStateDepth == 0; i++) {
+  for (uint32_t i = 0; i < length && aTopWindow->mModalStateDepth == 0; i++) {
     nsCOMPtr<nsIDOMWindow> child;
     frames->Item(i, getter_AddRefs(child));
 
@@ -9110,10 +8351,7 @@ nsGlobalWindow::RunPendingTimeoutsRecursive(nsGlobalWindow *aTopWindow,
       return;
     }
 
-    nsGlobalWindow *childWin =
-      static_cast<nsGlobalWindow *>
-                 (static_cast<nsIDOMWindow *>
-                             (child.get()));
+    auto* childWin = static_cast<nsGlobalWindow*>(child.get());
 
     RunPendingTimeoutsRecursive(aTopWindow, childWin);
   }
@@ -9144,7 +8382,7 @@ nsGlobalWindow::LeaveModalState()
 {
   MOZ_ASSERT(IsOuterWindow(), "Modal state is maintained on outer windows");
 
-  nsGlobalWindow* topWin = GetScriptableTop();
+  nsGlobalWindow* topWin = GetScriptableTopInternal();
 
   if (!topWin) {
     NS_ERROR("Uh, LeaveModalState() called w/o a reachable top window?");
@@ -9184,7 +8422,7 @@ nsGlobalWindow::LeaveModalState()
 bool
 nsGlobalWindow::IsInModalState()
 {
-  nsGlobalWindow *topWin = GetScriptableTop();
+  nsGlobalWindow *topWin = GetScriptableTopInternal();
 
   if (!topWin) {
     // IsInModalState() getting called w/o a reachable top window is a bit
@@ -9341,29 +8579,6 @@ nsGlobalWindow::CacheXBLPrototypeHandler(nsXBLPrototypeHandler* aKey,
   mCachedXBLPrototypeHandlers->Put(aKey, aHandler);
 }
 
-/**
- * GetScriptableFrameElement is called when script reads
- * nsIGlobalWindow::frameElement.
- *
- * In contrast to GetRealFrameElement, GetScriptableFrameElement says that the
- * window contained by an <iframe mozbrowser> or <iframe mozapp> has no frame
- * element (effectively treating a mozbrowser the same as a content/chrome
- * boundary).
- */
-NS_IMETHODIMP
-nsGlobalWindow::GetScriptableFrameElement(nsIDOMElement** aFrameElement)
-{
-  ErrorResult rv;
-  nsCOMPtr<nsIDOMElement> frameElement = do_QueryInterface(GetFrameElement(rv));
-  if (rv.Failed()) {
-    return rv.StealNSResult();
-  }
-
-  frameElement.forget(aFrameElement);
-
-  return NS_OK;
-}
-
 Element*
 nsGlobalWindow::GetFrameElementOuter()
 {
@@ -9424,17 +8639,16 @@ nsGlobalWindow::GetRealFrameElement(ErrorResult& aError)
  * nsIGlobalWindow::GetFrameElement (when called from C++) is just a wrapper
  * around GetRealFrameElement.
  */
-NS_IMETHODIMP
-nsGlobalWindow::GetRealFrameElement(nsIDOMElement** aFrameElement)
+already_AddRefed<nsIDOMElement>
+nsGlobalWindow::GetFrameElement()
 {
-  FORWARD_TO_INNER(GetRealFrameElement, (aFrameElement), NS_ERROR_UNEXPECTED);
+  FORWARD_TO_INNER(GetFrameElement, (), nullptr);
 
-  ErrorResult rv;
+  ErrorResult dummy;
   nsCOMPtr<nsIDOMElement> frameElement =
-    do_QueryInterface(GetRealFrameElement(rv));
-  frameElement.forget(aFrameElement);
-
-  return rv.StealNSResult();
+    do_QueryInterface(GetRealFrameElement(dummy));
+  dummy.SuppressException();
+  return frameElement.forget();
 }
 
 /* static */ bool
@@ -9677,29 +8891,6 @@ nsGlobalWindow::ShowModalDialog(JSContext* aCx, const nsAString& aUrl,
   }
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::ShowModalDialog(const nsAString& aURI, nsIVariant *aArgs_,
-                                const nsAString& aOptions, uint8_t aArgc,
-                                nsIVariant **aRetVal)
-{
-  FORWARD_TO_INNER(ShowModalDialog, (aURI, aArgs_, aOptions, aArgc, aRetVal),
-                   NS_ERROR_UNEXPECTED);
-
-  // Per-spec the |arguments| parameter is supposed to pass through unmodified.
-  // However, XPConnect default-initializes variants to null, rather than
-  // undefined. Fix this up here.
-  nsCOMPtr<nsIVariant> aArgs = aArgs_;
-  if (aArgc < 1) {
-    aArgs = CreateVoidVariant();
-  }
-
-  ErrorResult rv;
-  nsCOMPtr<nsIVariant> retVal = ShowModalDialog(aURI, aArgs, aOptions, rv);
-  retVal.forget(aRetVal);
-
-  return rv.StealNSResult();
-}
-
 class ChildCommandDispatcher : public nsRunnable
 {
 public:
@@ -9746,7 +8937,7 @@ public:
   nsString                             mAction;
 };
 
-NS_IMETHODIMP
+nsresult
 nsGlobalWindow::UpdateCommands(const nsAString& anAction, nsISelection* aSel, int16_t aReason)
 {
   // If this is a child process, redirect to the parent process.
@@ -9800,16 +8991,11 @@ nsGlobalWindow::GetSelection(ErrorResult& aError)
   FORWARD_TO_OUTER_OR_THROW(GetSelectionOuter, (), aError, nullptr);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetSelection(nsISelection** aSelection)
+already_AddRefed<nsISelection>
+nsGlobalWindow::GetSelection()
 {
-  FORWARD_TO_INNER(GetSelection, (aSelection), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  nsCOMPtr<nsISelection> selection = GetSelection(rv);
-  selection.forget(aSelection);
-
-  return rv.StealNSResult();
+  nsCOMPtr<nsISelection> selection = GetSelectionOuter();
+  return selection.forget();
 }
 
 bool
@@ -9865,9 +9051,9 @@ nsGlobalWindow::FindOuter(const nsAString& aString, bool aCaseSensitive,
                                           getter_AddRefs(findDialog));
     }
 
-    if (findDialog) {
+    if (nsCOMPtr<nsPIDOMWindow> piFindDialog = do_QueryInterface(findDialog)) {
       // The Find dialog is already open, bring it to the top.
-      aError = findDialog->Focus();
+      aError = piFindDialog->Focus();
     } else if (finder) {
       // Open a Find dialog
       nsCOMPtr<nsIDOMWindow> dialog;
@@ -9898,24 +9084,6 @@ nsGlobalWindow::Find(const nsAString& aString, bool aCaseSensitive,
                             aError, false);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Find(const nsAString& aStr, bool aCaseSensitive,
-                     bool aBackwards, bool aWrapAround, bool aWholeWord,
-                     bool aSearchInFrames, bool aShowDialog,
-                     bool *aDidFind)
-{
-  FORWARD_TO_INNER(Find,
-                   (aStr, aCaseSensitive, aBackwards, aWrapAround, aWholeWord,
-                    aSearchInFrames, aShowDialog, aDidFind),
-                   NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  *aDidFind = Find(aStr, aCaseSensitive, aBackwards, aWrapAround, aWholeWord,
-                   aSearchInFrames, aShowDialog, rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::Atob(const nsAString& aAsciiBase64String,
                      nsAString& aBinaryData, ErrorResult& aError)
@@ -9924,18 +9092,6 @@ nsGlobalWindow::Atob(const nsAString& aAsciiBase64String,
   aError = nsContentUtils::Atob(aAsciiBase64String, aBinaryData);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Atob(const nsAString& aAsciiBase64String,
-                     nsAString& aBinaryData)
-{
-  FORWARD_TO_INNER(Atob, (aAsciiBase64String, aBinaryData), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  Atob(aAsciiBase64String, aBinaryData, rv);
-
-  return rv.StealNSResult();
-}
-
 void
 nsGlobalWindow::Btoa(const nsAString& aBinaryData,
                      nsAString& aAsciiBase64String, ErrorResult& aError)
@@ -9944,18 +9100,6 @@ nsGlobalWindow::Btoa(const nsAString& aBinaryData,
   aError = nsContentUtils::Btoa(aBinaryData, aAsciiBase64String);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::Btoa(const nsAString& aBinaryData,
-                     nsAString& aAsciiBase64String)
-{
-  FORWARD_TO_INNER(Btoa, (aBinaryData, aAsciiBase64String), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  Btoa(aBinaryData, aAsciiBase64String, rv);
-
-  return rv.StealNSResult();
-}
-
 //*****************************************************************************
 // nsGlobalWindow::nsIDOMEventTarget
 //*****************************************************************************
@@ -10126,10 +9270,9 @@ nsGlobalWindow::GetPrivateParent()
 {
   MOZ_ASSERT(IsOuterWindow());
 
-  nsCOMPtr<nsIDOMWindow> parent;
-  GetParent(getter_AddRefs(parent));
+  nsCOMPtr<nsPIDOMWindow> parent = GetParent();
 
-  if (static_cast<nsIDOMWindow *>(this) == parent.get()) {
+  if (static_cast<nsPIDOMWindow *>(this) == parent.get()) {
     nsCOMPtr<nsIContent> chromeElement(do_QueryInterface(mChromeEventHandler));
     if (!chromeElement)
       return nullptr;             // This is ok, just means a null parent.
@@ -10161,16 +9304,15 @@ nsGlobalWindow::GetPrivateRoot()
     return outer->GetPrivateRoot();
   }
 
-  nsCOMPtr<nsIDOMWindow> top;
-  GetTop(getter_AddRefs(top));
+  nsCOMPtr<nsPIDOMWindow> top = GetTop();
 
   nsCOMPtr<nsIContent> chromeElement(do_QueryInterface(mChromeEventHandler));
   if (chromeElement) {
     nsIDocument* doc = chromeElement->GetComposedDoc();
     if (doc) {
-      nsIDOMWindow *parent = doc->GetWindow();
+      nsCOMPtr<nsPIDOMWindow> parent = doc->GetWindow();
       if (parent) {
-        parent->GetTop(getter_AddRefs(top));
+        top = parent->GetTop();
       }
     }
   }
@@ -10190,16 +9332,15 @@ nsGlobalWindow::GetLocation(ErrorResult& aError)
   return mLocation;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetLocation(nsIDOMLocation ** aLocation)
+nsIDOMLocation*
+nsGlobalWindow::GetLocation()
 {
-  FORWARD_TO_INNER(GetLocation, (aLocation), NS_ERROR_UNEXPECTED);
+  FORWARD_TO_INNER(GetLocation, (), nullptr);
 
-  ErrorResult rv;
-  nsCOMPtr<nsIDOMLocation> location = GetLocation(rv);
-  location.forget(aLocation);
-
-  return rv.StealNSResult();
+  ErrorResult dummy;
+  nsIDOMLocation* location = GetLocation(dummy);
+  dummy.SuppressException();
+  return location;
 }
 
 void
@@ -10769,15 +9910,6 @@ nsGlobalWindow::GetComputedStyle(Element& aElt, const nsAString& aPseudoElt,
   return GetComputedStyleHelper(aElt, aPseudoElt, false, aError);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetComputedStyle(nsIDOMElement* aElt,
-                                 const nsAString& aPseudoElt,
-                                 nsIDOMCSSStyleDeclaration** aReturn)
-{
-  FORWARD_TO_INNER(GetComputedStyle, (aElt, aPseudoElt, aReturn), NS_ERROR_UNEXPECTED);
-  return GetComputedStyleHelper(aElt, aPseudoElt, false, aReturn);
-}
-
 already_AddRefed<nsICSSDeclaration>
 nsGlobalWindow::GetDefaultComputedStyle(Element& aElt,
                                         const nsAString& aPseudoElt,
@@ -10787,15 +9919,6 @@ nsGlobalWindow::GetDefaultComputedStyle(Element& aElt,
   return GetComputedStyleHelper(aElt, aPseudoElt, true, aError);
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetDefaultComputedStyle(nsIDOMElement* aElt,
-                                        const nsAString& aPseudoElt,
-                                        nsIDOMCSSStyleDeclaration** aReturn)
-{
-  FORWARD_TO_INNER(GetDefaultComputedStyle, (aElt, aPseudoElt, aReturn), NS_ERROR_UNEXPECTED);
-  return GetComputedStyleHelper(aElt, aPseudoElt, true, aReturn);
-}
-
 nsresult
 nsGlobalWindow::GetComputedStyleHelper(nsIDOMElement* aElt,
                                        const nsAString& aPseudoElt,
@@ -10953,18 +10076,6 @@ nsGlobalWindow::GetSessionStorage(ErrorResult& aError)
   return mSessionStorage;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetSessionStorage(nsISupports** aSessionStorage)
-{
-  FORWARD_TO_INNER(GetSessionStorage, (aSessionStorage), NS_ERROR_FAILURE);
-
-  ErrorResult rv;
-  nsCOMPtr<nsIDOMStorage> storage = GetSessionStorage(rv);
-  storage.forget(aSessionStorage);
-
-  return rv.StealNSResult();
-}
-
 DOMStorage*
 nsGlobalWindow::GetLocalStorage(ErrorResult& aError)
 {
@@ -11013,19 +10124,6 @@ nsGlobalWindow::GetLocalStorage(ErrorResult& aError)
   return mLocalStorage;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetLocalStorage(nsISupports** aLocalStorage)
-{
-  NS_ENSURE_ARG(aLocalStorage);
-  FORWARD_TO_INNER(GetLocalStorage, (aLocalStorage), NS_ERROR_UNEXPECTED);
-
-  ErrorResult rv;
-  nsCOMPtr<nsIDOMStorage> storage = GetLocalStorage(rv);
-  storage.forget(aLocalStorage);
-
-  return rv.StealNSResult();
-}
-
 IDBFactory*
 nsGlobalWindow::GetIndexedDB(ErrorResult& aError)
 {
@@ -11038,16 +10136,6 @@ nsGlobalWindow::GetIndexedDB(ErrorResult& aError)
   return mIndexedDB;
 }
 
-NS_IMETHODIMP
-nsGlobalWindow::GetIndexedDB(nsISupports** _retval)
-{
-  ErrorResult rv;
-  nsCOMPtr<nsISupports> request(GetIndexedDB(rv));
-  request.forget(_retval);
-
-  return rv.StealNSResult();
-}
-
 //*****************************************************************************
 // nsGlobalWindow::nsIInterfaceRequestor
 //*****************************************************************************
@@ -11946,8 +11034,7 @@ nsGlobalWindow::Observe(nsISupports* aSubject, const char* aTopic,
     // Instantiate the application object now. It observes update belonging to
     // this window's document and correctly updates the applicationCache object
     // state.
-    nsCOMPtr<nsIDOMOfflineResourceList> applicationCache;
-    GetApplicationCache(getter_AddRefs(applicationCache));
+    nsCOMPtr<nsIDOMOfflineResourceList> applicationCache = GetApplicationCache();
     nsCOMPtr<nsIObserver> observer = do_QueryInterface(applicationCache);
     if (observer)
       observer->Observe(aSubject, aTopic, aData);
@@ -12118,10 +11205,9 @@ nsGlobalWindow::GetParentInternal()
     return outer->GetParentInternal();
   }
 
-  nsCOMPtr<nsIDOMWindow> parent;
-  GetParent(getter_AddRefs(parent));
+  nsCOMPtr<nsPIDOMWindow> parent = GetParent();
 
-  if (parent && parent != static_cast<nsIDOMWindow *>(this)) {
+  if (parent && parent != static_cast<nsPIDOMWindow*>(this)) {
     return parent;
   }
 
@@ -12325,8 +11411,8 @@ nsGlobalWindow::OpenInternal(const nsAString& aUrl, const nsAString& aName,
       }
 #endif
 
-      nsCOMPtr<nsIDOMDocument> doc;
-      (*aReturn)->GetDocument(getter_AddRefs(doc));
+      // Force document creation.
+      nsCOMPtr<nsIDocument> doc = static_cast<nsPIDOMWindow*>(*aReturn)->GetDoc();
     }
   }
 
@@ -14533,7 +13619,6 @@ nsGlobalWindow::IsModalContentWindow(JSContext* aCx, JSObject* aGlobal)
   return xpc::WindowOrNull(aGlobal)->IsModalContentWindow();
 }
 
-
 #if defined(MOZ_WIDGET_ANDROID) || defined(MOZ_WIDGET_GONK)
 int16_t
 nsGlobalWindow::Orientation() const
@@ -14542,33 +13627,6 @@ nsGlobalWindow::Orientation() const
 }
 #endif
 
-NS_IMETHODIMP
-nsGlobalWindow::GetConsole(JSContext* aCx,
-                           JS::MutableHandle<JS::Value> aConsole)
-{
-  FORWARD_TO_INNER(GetConsole, (aCx, aConsole), NS_ERROR_FAILURE);
-
-  ErrorResult rv;
-  RefPtr<Console> console = GetConsole(rv);
-  if (rv.Failed()) {
-    return rv.StealNSResult();
-  }
-
-  if (!GetOrCreateDOMReflector(aCx, console, aConsole)) {
-    return NS_ERROR_FAILURE;
-  }
-
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsGlobalWindow::SetConsole(JSContext* aCx, JS::Handle<JS::Value> aValue)
-{
-  ErrorResult rv;
-  RedefineProperty(aCx, "console", aValue, rv);
-  return rv.StealNSResult();
-}
-
 Console*
 nsGlobalWindow::GetConsole(ErrorResult& aRv)
 {
diff --git a/dom/base/nsGlobalWindow.h b/dom/base/nsGlobalWindow.h
index 80b65962825..8ce4d5beea3 100644
--- a/dom/base/nsGlobalWindow.h
+++ b/dom/base/nsGlobalWindow.h
@@ -526,31 +526,21 @@ public:
   {
     return FromSupports(wrapper->Native());
   }
-
-  /**
-   * Wrap nsIDOMWindow::GetTop so we can overload the inline GetTop()
-   * implementation below.  (nsIDOMWindow::GetTop simply calls
-   * nsIDOMWindow::GetRealTop().)
-   */
-  nsresult GetTop(nsIDOMWindow **aWindow)
+  already_AddRefed<nsPIDOMWindow> GetTop() override;
+  nsPIDOMWindow* GetScriptableTop() override;
+  inline nsGlobalWindow *GetTopInternal()
   {
-    return nsIDOMWindow::GetTop(aWindow);
-  }
-
-  inline nsGlobalWindow *GetTop()
-  {
-    nsCOMPtr<nsIDOMWindow> top;
-    GetTop(getter_AddRefs(top));
+    nsGlobalWindow* outer = IsOuterWindow() ? this : GetOuterWindowInternal();
+    nsCOMPtr<nsPIDOMWindow> top = outer ? outer->GetTop() : nullptr;
     if (top)
       return static_cast<nsGlobalWindow *>(top.get());
     return nullptr;
   }
 
-  inline nsGlobalWindow* GetScriptableTop()
+  inline nsGlobalWindow* GetScriptableTopInternal()
   {
-    nsCOMPtr<nsIDOMWindow> top;
-    GetScriptableTop(getter_AddRefs(top));
-    return static_cast<nsGlobalWindow *>(top.get());
+    nsPIDOMWindow* top = GetScriptableTop();
+    return static_cast<nsGlobalWindow*>(top);
   }
 
   nsPIDOMWindow* GetChildWindow(const nsAString& aName);
@@ -695,13 +685,8 @@ public:
   IsTopLevelWindow()
   {
     MOZ_ASSERT(IsOuterWindow());
-    nsCOMPtr<nsIDOMWindow> parentWindow;
-    nsresult rv = GetScriptableTop(getter_AddRefs(parentWindow));
-    if (NS_WARN_IF(NS_FAILED(rv))) {
-      return false;
-    }
-
-    return parentWindow == static_cast<nsIDOMWindow*>(this);
+    nsPIDOMWindow* parentWindow = GetScriptableTop();
+    return parentWindow == static_cast<nsPIDOMWindow*>(this);
   }
 
   virtual void
@@ -862,6 +847,7 @@ public:
   void SetNameOuter(const nsAString& aName, mozilla::ErrorResult& aError);
   void SetName(const nsAString& aName, mozilla::ErrorResult& aError);
   nsLocation* GetLocation(mozilla::ErrorResult& aError);
+  nsIDOMLocation* GetLocation() override;
   nsHistory* GetHistory(mozilla::ErrorResult& aError);
   mozilla::dom::BarProp* GetLocationbar(mozilla::ErrorResult& aError);
   mozilla::dom::BarProp* GetMenubar(mozilla::ErrorResult& aError);
@@ -875,35 +861,44 @@ public:
   void SetStatus(const nsAString& aStatus, mozilla::ErrorResult& aError);
   void CloseOuter(bool aTrustedCaller);
   void Close(mozilla::ErrorResult& aError);
+  nsresult Close() override;
   bool GetClosedOuter();
   bool GetClosed(mozilla::ErrorResult& aError);
+  bool Closed() override;
   void StopOuter(mozilla::ErrorResult& aError);
   void Stop(mozilla::ErrorResult& aError);
   void FocusOuter(mozilla::ErrorResult& aError);
   void Focus(mozilla::ErrorResult& aError);
+  nsresult Focus() override;
   void BlurOuter();
   void Blur(mozilla::ErrorResult& aError);
   already_AddRefed<nsIDOMWindow> GetFramesOuter();
+  already_AddRefed<nsIDOMWindowCollection> GetFrames() override;
   already_AddRefed<nsIDOMWindow> GetFrames(mozilla::ErrorResult& aError);
   uint32_t Length();
-  already_AddRefed<nsIDOMWindow> GetTopOuter(mozilla::ErrorResult& aError);
+  already_AddRefed<nsIDOMWindow> GetTopOuter();
   already_AddRefed<nsIDOMWindow> GetTop(mozilla::ErrorResult& aError);
+
+  nsresult GetPrompter(nsIPrompt** aPrompt) override;
 protected:
   explicit nsGlobalWindow(nsGlobalWindow *aOuterWindow);
-  nsIDOMWindow* GetOpenerWindowOuter();
-  nsIDOMWindow* GetOpenerWindow(mozilla::ErrorResult& aError);
+  nsPIDOMWindow* GetOpenerWindowOuter();
+  nsPIDOMWindow* GetOpenerWindow(mozilla::ErrorResult& aError);
   // Initializes the mWasOffline member variable
   void InitWasOffline();
 public:
   void GetOpener(JSContext* aCx, JS::MutableHandle<JS::Value> aRetval,
                  mozilla::ErrorResult& aError);
+  already_AddRefed<nsPIDOMWindow> GetOpener() override;
   void SetOpener(JSContext* aCx, JS::Handle<JS::Value> aOpener,
                  mozilla::ErrorResult& aError);
-  using nsIDOMWindow::GetParent;
-  already_AddRefed<nsIDOMWindow> GetParentOuter(mozilla::ErrorResult& aError);
+  already_AddRefed<nsIDOMWindow> GetParentOuter();
   already_AddRefed<nsIDOMWindow> GetParent(mozilla::ErrorResult& aError);
+  already_AddRefed<nsPIDOMWindow> GetParent() override;
+  nsPIDOMWindow* GetScriptableParent() override;
   mozilla::dom::Element* GetFrameElementOuter();
   mozilla::dom::Element* GetFrameElement(mozilla::ErrorResult& aError);
+  already_AddRefed<nsIDOMElement> GetFrameElement() override;
   already_AddRefed<nsIDOMWindow> OpenOuter(const nsAString& aUrl,
                                            const nsAString& aName,
                                            const nsAString& aOptions,
@@ -912,8 +907,12 @@ public:
                                       const nsAString& aName,
                                       const nsAString& aOptions,
                                       mozilla::ErrorResult& aError);
+  nsresult Open(const nsAString& aUrl, const nsAString& aName,
+                const nsAString& aOptions, nsPIDOMWindow **_retval) override;
   mozilla::dom::Navigator* GetNavigator(mozilla::ErrorResult& aError);
+  nsIDOMNavigator* GetNavigator() override;
   nsIDOMOfflineResourceList* GetApplicationCache(mozilla::ErrorResult& aError);
+  already_AddRefed<nsIDOMOfflineResourceList> GetApplicationCache() override;
 
 #if defined(MOZ_WIDGET_ANDROID) || defined(MOZ_WIDGET_GONK)
   int16_t Orientation() const;
@@ -987,18 +986,21 @@ public:
   mozilla::dom::DOMStorage* GetLocalStorage(mozilla::ErrorResult& aError);
   mozilla::dom::Selection* GetSelectionOuter();
   mozilla::dom::Selection* GetSelection(mozilla::ErrorResult& aError);
+  already_AddRefed<nsISelection> GetSelection() override;
   mozilla::dom::indexedDB::IDBFactory* GetIndexedDB(mozilla::ErrorResult& aError);
   already_AddRefed<nsICSSDeclaration>
     GetComputedStyle(mozilla::dom::Element& aElt, const nsAString& aPseudoElt,
-                     mozilla::ErrorResult& aError);
+                     mozilla::ErrorResult& aError) override;
   already_AddRefed<mozilla::dom::MediaQueryList> MatchMediaOuter(const nsAString& aQuery);
   already_AddRefed<mozilla::dom::MediaQueryList> MatchMedia(const nsAString& aQuery,
                                                             mozilla::ErrorResult& aError);
   nsScreen* GetScreen(mozilla::ErrorResult& aError);
+  nsIDOMScreen* GetScreen() override;
   void MoveToOuter(int32_t aXPos, int32_t aYPos, mozilla::ErrorResult& aError, bool aCallerIsChrome);
   void MoveTo(int32_t aXPos, int32_t aYPos, mozilla::ErrorResult& aError);
   void MoveByOuter(int32_t aXDif, int32_t aYDif, mozilla::ErrorResult& aError, bool aCallerIsChrome);
   void MoveBy(int32_t aXDif, int32_t aYDif, mozilla::ErrorResult& aError);
+  nsresult MoveBy(int32_t aXDif, int32_t aYDif) override;
   void ResizeToOuter(int32_t aWidth, int32_t aHeight, mozilla::ErrorResult& aError, bool aCallerIsChrome);
   void ResizeTo(int32_t aWidth, int32_t aHeight,
                 mozilla::ErrorResult& aError);
@@ -1069,6 +1071,7 @@ public:
   mozilla::dom::Crypto* GetCrypto(mozilla::ErrorResult& aError);
   nsIControllers* GetControllersOuter(mozilla::ErrorResult& aError);
   nsIControllers* GetControllers(mozilla::ErrorResult& aError);
+  nsresult GetControllers(nsIControllers** aControllers) override;
   mozilla::dom::Element* GetRealFrameElementOuter();
   mozilla::dom::Element* GetRealFrameElement(mozilla::ErrorResult& aError);
   float GetMozInnerScreenXOuter();
@@ -1077,12 +1080,17 @@ public:
   float GetMozInnerScreenY(mozilla::ErrorResult& aError);
   float GetDevicePixelRatioOuter();
   float GetDevicePixelRatio(mozilla::ErrorResult& aError);
+  nsresult GetDevicePixelRatio(float* aRatio) override;
+  int32_t GetScrollMinX(mozilla::ErrorResult& aError);
+  int32_t GetScrollMinY(mozilla::ErrorResult& aError);
   int32_t GetScrollMaxX(mozilla::ErrorResult& aError);
   int32_t GetScrollMaxY(mozilla::ErrorResult& aError);
   bool GetFullScreenOuter();
   bool GetFullScreen(mozilla::ErrorResult& aError);
+  bool GetFullScreen() override;
   void SetFullScreenOuter(bool aFullScreen, mozilla::ErrorResult& aError);
   void SetFullScreen(bool aFullScreen, mozilla::ErrorResult& aError);
+  nsresult SetFullScreen(bool aFullScreen) override;
   void BackOuter(mozilla::ErrorResult& aError);
   void Back(mozilla::ErrorResult& aError);
   void ForwardOuter(mozilla::ErrorResult& aError);
@@ -1114,6 +1122,10 @@ public:
                                             const nsAString& aOptions,
                                             const mozilla::dom::Sequence<JS::Value>& aExtraArgument,
                                             mozilla::ErrorResult& aError);
+  nsresult OpenDialog(const nsAString& aUrl, const nsAString& aName,
+                      const nsAString& aOptions,
+                      nsISupports* aExtraArgument, nsIDOMWindow** _retval) override;
+  nsresult UpdateCommands(const nsAString& anAction, nsISelection* aSel, int16_t aReason) override;
 
   already_AddRefed<nsIDOMWindow>
     GetContentInternal(mozilla::ErrorResult& aError, bool aUnprivilegedCaller);
@@ -1217,12 +1229,18 @@ protected:
                                  const char* aPropName,
                                  mozilla::ErrorResult& aError);
   // And the implementations of WindowCoordGetter/WindowCoordSetter.
+public:
   int32_t GetInnerWidthOuter(mozilla::ErrorResult& aError);
+protected:
   int32_t GetInnerWidth(mozilla::ErrorResult& aError);
+  nsresult GetInnerWidth(int32_t* aWidth) override;
   void SetInnerWidthOuter(int32_t aInnerWidth, mozilla::ErrorResult& aError, bool aCallerIsChrome);
   void SetInnerWidth(int32_t aInnerWidth, mozilla::ErrorResult& aError);
+public:
   int32_t GetInnerHeightOuter(mozilla::ErrorResult& aError);
+protected:
   int32_t GetInnerHeight(mozilla::ErrorResult& aError);
+  nsresult GetInnerHeight(int32_t* aHeight) override;
   void SetInnerHeightOuter(int32_t aInnerHeight, mozilla::ErrorResult& aError, bool aCallerIsChrome);
   void SetInnerHeight(int32_t aInnerHeight, mozilla::ErrorResult& aError);
   int32_t GetScreenXOuter(mozilla::ErrorResult& aError);
@@ -1490,9 +1508,7 @@ public:
   // Outer windows only.
   mozilla::CSSIntPoint GetScrollXY(bool aDoFlush);
 
-  void GetScrollMaxXYOuter(int32_t* aScrollMaxX, int32_t* aScrollMaxY);
-  void GetScrollMaxXY(int32_t* aScrollMaxX, int32_t* aScrollMaxY,
-                      mozilla::ErrorResult& aError);
+  int32_t GetScrollBoundaryOuter(mozilla::Side aSide);
 
   // Outer windows only.
   nsresult GetInnerSize(mozilla::CSSIntSize& aSize);
diff --git a/dom/base/nsMimeTypeArray.cpp b/dom/base/nsMimeTypeArray.cpp
index 3f5067b21f8..2e220761634 100644
--- a/dom/base/nsMimeTypeArray.cpp
+++ b/dom/base/nsMimeTypeArray.cpp
@@ -196,8 +196,7 @@ nsMimeTypeArray::EnsurePluginMimeTypes()
     return;
   }
 
-  nsCOMPtr<nsIDOMNavigator> navigator;
-  mWindow->GetNavigator(getter_AddRefs(navigator));
+  nsCOMPtr<nsIDOMNavigator> navigator = mWindow->GetNavigator();
 
   if (!navigator) {
     return;
diff --git a/dom/base/nsObjectLoadingContent.cpp b/dom/base/nsObjectLoadingContent.cpp
index 5deb4c8b8f3..7d008f71c1b 100644
--- a/dom/base/nsObjectLoadingContent.cpp
+++ b/dom/base/nsObjectLoadingContent.cpp
@@ -3300,17 +3300,14 @@ nsObjectLoadingContent::ShouldPlay(FallbackType &aReason, bool aIgnoreCurrentTyp
   MOZ_ASSERT(thisContent);
   nsIDocument* ownerDoc = thisContent->OwnerDoc();
 
-  nsCOMPtr<nsIDOMWindow> window = ownerDoc->GetWindow();
+  nsCOMPtr<nsPIDOMWindow> window = ownerDoc->GetWindow();
   if (!window) {
     return false;
   }
-  nsCOMPtr<nsIDOMWindow> topWindow;
-  rv = window->GetTop(getter_AddRefs(topWindow));
-  NS_ENSURE_SUCCESS(rv, false);
-  nsCOMPtr<nsIDOMDocument> topDocument;
-  rv = topWindow->GetDocument(getter_AddRefs(topDocument));
-  NS_ENSURE_SUCCESS(rv, false);
-  nsCOMPtr<nsIDocument> topDoc = do_QueryInterface(topDocument);
+  nsCOMPtr<nsPIDOMWindow> topWindow = window->GetTop();
+  NS_ENSURE_TRUE(topWindow, false);
+  nsCOMPtr<nsIDocument> topDoc = topWindow->GetDoc();
+  NS_ENSURE_TRUE(topDoc, false);
 
   nsCOMPtr<nsIPermissionManager> permissionManager = services::GetPermissionManager();
   NS_ENSURE_TRUE(permissionManager, false);
diff --git a/dom/base/nsPIDOMWindow.h b/dom/base/nsPIDOMWindow.h
index d40a85d74bc..e4255c181f8 100644
--- a/dom/base/nsPIDOMWindow.h
+++ b/dom/base/nsPIDOMWindow.h
@@ -22,6 +22,7 @@
 
 class nsIArray;
 class nsIContent;
+class nsICSSDeclaration;
 class nsIDocShell;
 class nsIDocument;
 class nsIIdleObserver;
@@ -62,8 +63,8 @@ enum UIStateChangeType
 };
 
 #define NS_PIDOMWINDOW_IID \
-{ 0x052e675a, 0xacd3, 0x48d1, \
-  { 0x8a, 0xcd, 0xbf, 0xff, 0xbd, 0x24, 0x4c, 0xed } }
+{ 0x775dabc9, 0x8f43, 0x4277, \
+  { 0x9a, 0xdb, 0xf1, 0x99, 0x0d, 0x77, 0xcf, 0xfb } }
 
 class nsPIDOMWindow : public nsIDOMWindowInternal
 {
@@ -76,6 +77,23 @@ public:
   virtual void ActivateOrDeactivate(bool aActivate) = 0;
 
   // this is called GetTopWindowRoot to avoid conflicts with nsIDOMWindow::GetWindowRoot
+  /**
+   * |top| gets the root of the window hierarchy.
+   *
+   * This function does not cross chrome-content boundaries, so if this
+   * window's parent is of a different type, |top| will return this window.
+   *
+   * When script reads the top property, we run GetScriptableTop, which
+   * will not cross an <iframe mozbrowser> boundary.
+   *
+   * In contrast, C++ calls to GetTop are forwarded to GetRealTop, which
+   * ignores <iframe mozbrowser> boundaries.
+   */
+
+  virtual already_AddRefed<nsPIDOMWindow> GetTop() = 0; // Outer only
+  virtual already_AddRefed<nsPIDOMWindow> GetParent() = 0;
+  virtual nsPIDOMWindow* GetScriptableTop() = 0;
+  virtual nsPIDOMWindow* GetScriptableParent() = 0;
   virtual already_AddRefed<nsPIWindowRoot> GetTopWindowRoot() = 0;
 
   // Inner windows only.
@@ -763,6 +781,38 @@ public:
     return mMarkedCCGeneration;
   }
 
+  virtual nsIDOMScreen* GetScreen() = 0;
+  virtual nsIDOMNavigator* GetNavigator() = 0;
+  virtual nsIDOMLocation* GetLocation() = 0;
+  virtual nsresult GetPrompter(nsIPrompt** aPrompt) = 0;
+  virtual nsresult GetControllers(nsIControllers** aControllers) = 0;
+  virtual already_AddRefed<nsISelection> GetSelection() = 0;
+  virtual already_AddRefed<nsPIDOMWindow> GetOpener() = 0;
+  virtual already_AddRefed<nsIDOMWindowCollection> GetFrames() = 0;
+  virtual nsresult Open(const nsAString& aUrl, const nsAString& aName,
+                        const nsAString& aOptions, nsPIDOMWindow **_retval) = 0;
+  virtual nsresult OpenDialog(const nsAString& aUrl, const nsAString& aName,
+                              const nsAString& aOptions,
+                              nsISupports* aExtraArgument, nsIDOMWindow** _retval) = 0;
+
+  virtual nsresult GetDevicePixelRatio(float* aRatio) = 0;
+  virtual nsresult GetInnerWidth(int32_t* aWidth) = 0;
+  virtual nsresult GetInnerHeight(int32_t* aHeight) = 0;
+  virtual already_AddRefed<nsICSSDeclaration>
+    GetComputedStyle(mozilla::dom::Element& aElt, const nsAString& aPseudoElt,
+                     mozilla::ErrorResult& aError) = 0;
+  virtual already_AddRefed<nsIDOMElement> GetFrameElement() = 0;
+  virtual already_AddRefed<nsIDOMOfflineResourceList> GetApplicationCache() = 0;
+  virtual bool Closed() = 0;
+  virtual bool GetFullScreen() = 0;
+  virtual nsresult SetFullScreen(bool aFullScreen) = 0;
+
+  virtual nsresult Focus() = 0;
+  virtual nsresult Close() = 0;
+
+  virtual nsresult MoveBy(int32_t aXDif, int32_t aYDif) = 0;
+  virtual nsresult UpdateCommands(const nsAString& anAction, nsISelection* aSel, int16_t aReason) = 0;
+
 protected:
   // The nsPIDOMWindow constructor. The aOuterWindow argument should
   // be null if and only if the created window itself is an outer
diff --git a/dom/base/nsPluginArray.cpp b/dom/base/nsPluginArray.cpp
index 857184c1ea1..eba3127a2fa 100644
--- a/dom/base/nsPluginArray.cpp
+++ b/dom/base/nsPluginArray.cpp
@@ -147,8 +147,7 @@ nsPluginArray::Refresh(bool aReloadDocuments)
 
   mPlugins.Clear();
 
-  nsCOMPtr<nsIDOMNavigator> navigator;
-  mWindow->GetNavigator(getter_AddRefs(navigator));
+  nsCOMPtr<nsIDOMNavigator> navigator = mWindow->GetNavigator();
 
   if (!navigator) {
     return;
diff --git a/dom/base/nsScreen.cpp b/dom/base/nsScreen.cpp
index 83685cff0d2..ad1642b2d24 100644
--- a/dom/base/nsScreen.cpp
+++ b/dom/base/nsScreen.cpp
@@ -312,7 +312,7 @@ nsScreen::GetWindowInnerRect(nsRect& aRect)
 {
   aRect.x = 0;
   aRect.y = 0;
-  nsCOMPtr<nsIDOMWindow> win = GetOwner();
+  nsCOMPtr<nsPIDOMWindow> win = GetOwner();
   if (!win) {
     return NS_ERROR_FAILURE;
   }
diff --git a/dom/base/nsWindowMemoryReporter.cpp b/dom/base/nsWindowMemoryReporter.cpp
index d03a5a866c2..7026716a180 100644
--- a/dom/base/nsWindowMemoryReporter.cpp
+++ b/dom/base/nsWindowMemoryReporter.cpp
@@ -63,12 +63,10 @@ AddNonJSSizeOfWindowAndItsDescendents(nsGlobalWindow* aWindow,
     innerWindowSizes.addToTabSizes(aSizes);
   }
 
-  nsCOMPtr<nsIDOMWindowCollection> frames;
-  nsresult rv = aWindow->GetFrames(getter_AddRefs(frames));
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsIDOMWindowCollection> frames = aWindow->GetFrames();
 
   uint32_t length;
-  rv = frames->GetLength(&length);
+  nsresult rv = frames->GetLength(&length);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // Measure this window's descendents.
@@ -252,8 +250,8 @@ CollectWindowReports(nsGlobalWindow *aWindow,
   nsCOMPtr<nsIURI> location;
   if (aWindow->GetOuterWindow()) {
     // Our window should have a null top iff it has a null docshell.
-    MOZ_ASSERT(!!aWindow->GetTop() == !!aWindow->GetDocShell());
-    top = aWindow->GetTop();
+    MOZ_ASSERT(!!aWindow->GetTopInternal() == !!aWindow->GetDocShell());
+    top = aWindow->GetTopInternal();
     if (top) {
       location = GetWindowURI(top);
     }
@@ -747,9 +745,9 @@ CheckForGhostWindowsEnumerator(nsISupports *aKey, TimeStamp& aTimeStamp,
   // Avoid calling GetTop() if we have no outer window.  Nothing will break if
   // we do, but it will spew debug output, which can cause our test logs to
   // overflow.
-  nsCOMPtr<nsIDOMWindow> top;
+  nsCOMPtr<nsPIDOMWindow> top;
   if (window->GetOuterWindow()) {
-    window->GetTop(getter_AddRefs(top));
+    top = window->GetOuterWindow()->GetTop();
   }
 
   if (top) {
@@ -806,7 +804,7 @@ GetNonDetachedWindowDomainsEnumerator(const uint64_t& aId, nsGlobalWindow* aWind
 
   // Null outer window implies null top, but calling GetTop() when there's no
   // outer window causes us to spew debug warnings.
-  if (!aWindow->GetOuterWindow() || !aWindow->GetTop()) {
+  if (!aWindow->GetOuterWindow() || !aWindow->GetTopInternal()) {
     // This window is detached, so we don't care about its domain.
     return PL_DHASH_NEXT;
   }
diff --git a/dom/base/nsWindowRoot.cpp b/dom/base/nsWindowRoot.cpp
index 285d77b07e1..defdb243e0a 100644
--- a/dom/base/nsWindowRoot.cpp
+++ b/dom/base/nsWindowRoot.cpp
@@ -242,7 +242,7 @@ nsWindowRoot::GetControllers(nsIControllers** aResult)
       return focusedWindow->GetControllers(aResult);
   }
   else {
-    nsCOMPtr<nsIDOMWindow> domWindow = do_QueryInterface(focusedWindow);
+    nsCOMPtr<nsPIDOMWindow> domWindow = do_QueryInterface(focusedWindow);
     if (domWindow)
       return domWindow->GetControllers(aResult);
   }
diff --git a/dom/base/nsXMLHttpRequest.cpp b/dom/base/nsXMLHttpRequest.cpp
index 27517aa24ed..1bc30c752ac 100644
--- a/dom/base/nsXMLHttpRequest.cpp
+++ b/dom/base/nsXMLHttpRequest.cpp
@@ -2941,17 +2941,15 @@ nsXMLHttpRequest::Send(nsIVariant* aVariant, const Nullable<RequestBody>& aBody)
     nsCOMPtr<nsIDocument> suspendedDoc;
     nsCOMPtr<nsIRunnable> resumeTimeoutRunnable;
     if (GetOwner()) {
-      nsCOMPtr<nsIDOMWindow> topWindow;
-      if (NS_SUCCEEDED(GetOwner()->GetTop(getter_AddRefs(topWindow)))) {
-        nsCOMPtr<nsPIDOMWindow> suspendedWindow(do_QueryInterface(topWindow));
-        if (suspendedWindow &&
-            (suspendedWindow = suspendedWindow->GetCurrentInnerWindow())) {
-          suspendedDoc = suspendedWindow->GetExtantDoc();
+      if (nsCOMPtr<nsPIDOMWindow> topWindow = GetOwner()->GetOuterWindow()->GetTop()) {
+        if (topWindow &&
+            (topWindow = topWindow->GetCurrentInnerWindow())) {
+          suspendedDoc = topWindow->GetExtantDoc();
           if (suspendedDoc) {
             suspendedDoc->SuppressEventHandling(nsIDocument::eEvents);
           }
-          suspendedWindow->SuspendTimeouts(1, false);
-          resumeTimeoutRunnable = new nsResumeTimeoutsEvent(suspendedWindow);
+          topWindow->SuspendTimeouts(1, false);
+          resumeTimeoutRunnable = new nsResumeTimeoutsEvent(topWindow);
         }
       }
     }
diff --git a/dom/browser-element/BrowserElementAudioChannel.cpp b/dom/browser-element/BrowserElementAudioChannel.cpp
index 09d4e45b258..8aa5f73183e 100644
--- a/dom/browser-element/BrowserElementAudioChannel.cpp
+++ b/dom/browser-element/BrowserElementAudioChannel.cpp
@@ -117,10 +117,7 @@ BrowserElementAudioChannel::Initialize()
       return NS_ERROR_FAILURE;
     }
 
-    nsCOMPtr<nsIDOMWindow> topWindow;
-    window->GetScriptableTop(getter_AddRefs(topWindow));
-
-    mFrameWindow = do_QueryInterface(topWindow);
+    mFrameWindow = window->GetScriptableTop();
     mFrameWindow = mFrameWindow->GetOuterWindow();
     return NS_OK;
   }
@@ -137,10 +134,7 @@ BrowserElementAudioChannel::Initialize()
       return NS_ERROR_FAILURE;
     }
 
-    nsCOMPtr<nsIDOMWindow> topWindow;
-    window->GetScriptableTop(getter_AddRefs(topWindow));
-
-    mFrameWindow = do_QueryInterface(topWindow);
+    mFrameWindow = window->GetScriptableTop();
     mFrameWindow = mFrameWindow->GetOuterWindow();
     return NS_OK;
   }
diff --git a/dom/browser-element/BrowserElementPanningAPZDisabled.js b/dom/browser-element/BrowserElementPanningAPZDisabled.js
index 662ee98962a..f45399b4d7e 100644
--- a/dom/browser-element/BrowserElementPanningAPZDisabled.js
+++ b/dom/browser-element/BrowserElementPanningAPZDisabled.js
@@ -348,8 +348,10 @@ const ContentPanningAPZDisabled = {
       let isScrollableTextarea = (node.tagName == 'TEXTAREA' &&
           (node.scrollHeight > node.clientHeight ||
            node.scrollWidth > node.clientWidth ||
-           ('scrollLeftMax' in node && node.scrollLeftMax > 0) ||
-           ('scrollTopMax' in node && node.scrollTopMax > 0)));
+           ('scrollLeftMin' in node && 'scrollLeftMax' in node &&
+            node.scrollLeftMin != node.scrollLeftMax) ||
+           ('scrollTopMin' in node && 'scrollTopMax' in node &&
+            node.scrollTopMin != node.scrollTopMax)));
       if (isScroll || isAuto || isScrollableTextarea) {
         return node;
       }
@@ -357,7 +359,8 @@ const ContentPanningAPZDisabled = {
       node = node.parentNode;
     }
 
-    if (nodeContent.scrollMaxX || nodeContent.scrollMaxY) {
+    if (nodeContent.scrollMaxX != nodeContent.scrollMinX ||
+        nodeContent.scrollMaxY != nodeContent.scrollMinY) {
       return nodeContent;
     }
 
diff --git a/dom/browser-element/BrowserElementParent.cpp b/dom/browser-element/BrowserElementParent.cpp
index f8385c92b12..015c33e4a5e 100644
--- a/dom/browser-element/BrowserElementParent.cpp
+++ b/dom/browser-element/BrowserElementParent.cpp
@@ -258,10 +258,8 @@ BrowserElementParent::OpenWindowInProcess(nsIDOMWindow* aOpenerWindow,
   // GetScriptableTop gets us the <iframe mozbrowser>'s window; we'll use its
   // frame element, rather than aOpenerWindow's frame element, as our "opener
   // frame element" below.
-  nsCOMPtr<nsIDOMWindow> topWindow;
-  aOpenerWindow->GetScriptableTop(getter_AddRefs(topWindow));
-
-  nsCOMPtr<nsPIDOMWindow> win = do_QueryInterface(topWindow);
+  nsCOMPtr<nsPIDOMWindow> openerWindow = do_QueryInterface(aOpenerWindow);
+  nsCOMPtr<nsPIDOMWindow> win = openerWindow->GetScriptableTop();
 
   nsCOMPtr<Element> openerFrameElement = win->GetFrameElementInternal();
   NS_ENSURE_TRUE(openerFrameElement, BrowserElementParent::OPEN_WINDOW_IGNORED);
diff --git a/dom/events/EventStateManager.cpp b/dom/events/EventStateManager.cpp
index 41bbd8eb181..6c1cc09482e 100644
--- a/dom/events/EventStateManager.cpp
+++ b/dom/events/EventStateManager.cpp
@@ -3023,17 +3023,17 @@ EventStateManager::PostHandleEvent(nsPresContext* aPresContext,
         EnsureDocument(mPresContext);
         nsIFocusManager* fm = nsFocusManager::GetFocusManager();
         if (mDocument && fm) {
-          nsCOMPtr<nsIDOMWindow> currentWindow;
-          fm->GetFocusedWindow(getter_AddRefs(currentWindow));
+          nsCOMPtr<nsIDOMWindow> window;
+          fm->GetFocusedWindow(getter_AddRefs(window));
+          nsCOMPtr<nsPIDOMWindow> currentWindow = do_QueryInterface(window);
           if (currentWindow && mDocument->GetWindow() &&
               currentWindow != mDocument->GetWindow() &&
               !nsContentUtils::IsChromeDoc(mDocument)) {
-            nsCOMPtr<nsIDOMWindow> currentTop;
-            nsCOMPtr<nsIDOMWindow> newTop;
-            currentWindow->GetTop(getter_AddRefs(currentTop));
-            mDocument->GetWindow()->GetTop(getter_AddRefs(newTop));
-            nsCOMPtr<nsPIDOMWindow> win = do_QueryInterface(currentWindow);
-            nsCOMPtr<nsIDocument> currentDoc = win->GetExtantDoc();
+            nsCOMPtr<nsPIDOMWindow> currentTop;
+            nsCOMPtr<nsPIDOMWindow> newTop;
+            currentTop = currentWindow->GetTop();
+            newTop = mDocument->GetWindow()->GetTop();
+            nsCOMPtr<nsIDocument> currentDoc = currentWindow->GetExtantDoc();
             if (nsContentUtils::IsChromeDoc(currentDoc) ||
                 (currentTop && newTop && currentTop != newTop)) {
               fm->SetFocusedWindow(mDocument->GetWindow());
@@ -4112,19 +4112,20 @@ GetWindowInnerRectCenter(nsPIDOMWindow* aWindow,
 {
   NS_ENSURE_TRUE(aWindow && aWidget && aContext, LayoutDeviceIntPoint(0, 0));
 
-  float cssInnerX = 0.0;
-  aWindow->GetMozInnerScreenX(&cssInnerX);
+  nsGlobalWindow* window = nsGlobalWindow::Cast(aWindow);
+
+  float cssInnerX = window->GetMozInnerScreenXOuter();
   int32_t innerX = int32_t(NS_round(cssInnerX));
 
-  float cssInnerY = 0.0;
-  aWindow->GetMozInnerScreenY(&cssInnerY);
+  float cssInnerY = window->GetMozInnerScreenYOuter();
   int32_t innerY = int32_t(NS_round(cssInnerY));
- 
-  int32_t innerWidth = 0;
-  aWindow->GetInnerWidth(&innerWidth);
 
-  int32_t innerHeight = 0;
-  aWindow->GetInnerHeight(&innerHeight);
+  ErrorResult dummy;
+  int32_t innerWidth = window->GetInnerWidthOuter(dummy);
+  dummy.SuppressException();
+
+  int32_t innerHeight = window->GetInnerHeightOuter(dummy);
+  dummy.SuppressException();
 
   nsIntRect screen;
   aWidget->GetScreenBounds(screen);
diff --git a/dom/events/IMEContentObserver.cpp b/dom/events/IMEContentObserver.cpp
index e4db31683f3..79c5c4e9a93 100644
--- a/dom/events/IMEContentObserver.cpp
+++ b/dom/events/IMEContentObserver.cpp
@@ -24,6 +24,7 @@
 #include "nsIDocument.h"
 #include "nsIDOMDocument.h"
 #include "nsIDOMRange.h"
+#include "nsIEditorIMESupport.h"
 #include "nsIFrame.h"
 #include "nsINode.h"
 #include "nsIPresShell.h"
@@ -589,6 +590,25 @@ IMEContentObserver::IsEditorHandlingEventForComposition() const
   return composition->IsEditorHandlingEvent();
 }
 
+bool
+IMEContentObserver::IsEditorComposing() const
+{
+  // Note that don't use TextComposition here. The important thing is,
+  // whether the editor already started to handle composition because
+  // web contents can change selection, text content and/or something from
+  // compositionstart event listener which is run before nsEditor handles it.
+  nsCOMPtr<nsIEditorIMESupport> editorIMESupport = do_QueryInterface(mEditor);
+  if (NS_WARN_IF(!editorIMESupport)) {
+    return false;
+  }
+  bool isComposing = false;
+  nsresult rv = editorIMESupport->GetComposing(&isComposing);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+  return isComposing;
+}
+
 nsresult
 IMEContentObserver::GetSelectionAndRoot(nsISelection** aSelection,
                                         nsIContent** aRootContent) const
@@ -614,8 +634,10 @@ IMEContentObserver::NotifySelectionChanged(nsIDOMDocument* aDOMDocument,
   if (count > 0 && mWidget) {
     bool causedByComposition = IsEditorHandlingEventForComposition();
     bool causedBySelectionEvent = TextComposition::IsHandlingSelectionEvent();
+    bool duringComposition = IsEditorComposing();
     MaybeNotifyIMEOfSelectionChange(causedByComposition,
-                                    causedBySelectionEvent);
+                                    causedBySelectionEvent,
+                                    duringComposition);
   }
   return NS_OK;
 }
@@ -825,7 +847,8 @@ IMEContentObserver::CharacterDataChanged(nsIDocument* aDocument,
   uint32_t oldEnd = offset + static_cast<uint32_t>(removedLength);
   uint32_t newEnd = offset + newLength;
 
-  TextChangeData data(offset, oldEnd, newEnd, causedByComposition);
+  TextChangeData data(offset, oldEnd, newEnd, causedByComposition,
+                      IsEditorComposing());
   MaybeNotifyIMEOfTextChange(data);
 }
 
@@ -878,7 +901,7 @@ IMEContentObserver::NotifyContentAdded(nsINode* aContainer,
   }
 
   TextChangeData data(offset, offset, offset + addingLength,
-                      causedByComposition);
+                      causedByComposition, IsEditorComposing());
   MaybeNotifyIMEOfTextChange(data);
 }
 
@@ -955,7 +978,8 @@ IMEContentObserver::ContentRemoved(nsIDocument* aDocument,
     return;
   }
 
-  TextChangeData data(offset, offset + textLength, offset, causedByComposition);
+  TextChangeData data(offset, offset + textLength, offset,
+                      causedByComposition, IsEditorComposing());
   MaybeNotifyIMEOfTextChange(data);
 }
 
@@ -1017,7 +1041,8 @@ IMEContentObserver::AttributeChanged(nsIDocument* aDocument,
   NS_ENSURE_SUCCESS_VOID(rv);
 
   TextChangeData data(start, start + mPreAttrChangeLength,
-                      start + postAttrChangeLength, causedByComposition);
+                      start + postAttrChangeLength, causedByComposition,
+                      IsEditorComposing());
   MaybeNotifyIMEOfTextChange(data);
 }
 
@@ -1140,15 +1165,18 @@ IMEContentObserver::MaybeNotifyIMEOfTextChange(
 void
 IMEContentObserver::MaybeNotifyIMEOfSelectionChange(
                       bool aCausedByComposition,
-                      bool aCausedBySelectionEvent)
+                      bool aCausedBySelectionEvent,
+                      bool aOccurredDuringComposition)
 {
   MOZ_LOG(sIMECOLog, LogLevel::Debug,
     ("IMECO: 0x%p IMEContentObserver::MaybeNotifyIMEOfSelectionChange("
-     "aCausedByComposition=%s, aCausedBySelectionEvent=%s)",
+     "aCausedByComposition=%s, aCausedBySelectionEvent=%s, "
+     "aOccurredDuringComposition)",
      this, ToChar(aCausedByComposition), ToChar(aCausedBySelectionEvent)));
 
   mSelectionData.AssignReason(aCausedByComposition,
-                              aCausedBySelectionEvent);
+                              aCausedBySelectionEvent,
+                              aOccurredDuringComposition);
   PostSelectionChangeNotification();
   FlushMergeableNotifications();
 }
diff --git a/dom/events/IMEContentObserver.h b/dom/events/IMEContentObserver.h
index 73559506b35..785b73d7c1c 100644
--- a/dom/events/IMEContentObserver.h
+++ b/dom/events/IMEContentObserver.h
@@ -122,6 +122,7 @@ private:
                           nsIContent* aContent) const;
   bool IsReflowLocked() const;
   bool IsSafeToNotifyIME() const;
+  bool IsEditorComposing() const;
 
   void PostFocusSetNotification();
   void MaybeNotifyIMEOfFocusSet();
@@ -129,7 +130,8 @@ private:
   void MaybeNotifyIMEOfTextChange(const TextChangeDataBase& aTextChangeData);
   void PostSelectionChangeNotification();
   void MaybeNotifyIMEOfSelectionChange(bool aCausedByComposition,
-                                       bool aCausedBySelectionEvent);
+                                       bool aCausedBySelectionEvent,
+                                       bool aOccurredDuringComposition);
   void PostPositionChangeNotification();
   void MaybeNotifyIMEOfPositionChange();
 
diff --git a/dom/geolocation/nsGeolocation.cpp b/dom/geolocation/nsGeolocation.cpp
index ab55cb8cb98..c22735ef5f9 100644
--- a/dom/geolocation/nsGeolocation.cpp
+++ b/dom/geolocation/nsGeolocation.cpp
@@ -1605,14 +1605,9 @@ Geolocation::WindowOwnerStillExists()
   nsCOMPtr<nsPIDOMWindow> window = do_QueryReferent(mOwner);
 
   if (window) {
-    bool closed = false;
-    window->GetClosed(&closed);
-    if (closed) {
-      return false;
-    }
-
     nsPIDOMWindow* outer = window->GetOuterWindow();
-    if (!outer || outer->GetCurrentInnerWindow() != window) {
+    if (!outer || outer->GetCurrentInnerWindow() != window ||
+        outer->Closed()) {
       return false;
     }
   }
diff --git a/dom/html/HTMLMediaElement.cpp b/dom/html/HTMLMediaElement.cpp
index 4bf38061da5..3562a64a06b 100644
--- a/dom/html/HTMLMediaElement.cpp
+++ b/dom/html/HTMLMediaElement.cpp
@@ -2268,7 +2268,7 @@ HTMLMediaElement::PlayInternal(bool aCallerIsChrome)
   }
 
   if (Preferences::GetBool("media.block-play-until-visible", false) &&
-      !nsContentUtils::IsCallerChrome() &&
+      !aCallerIsChrome &&
       OwnerDoc()->Hidden()) {
     LOG(LogLevel::Debug, ("%p Blocked playback because owner hidden.", this));
     mPlayBlockedBecauseHidden = true;
@@ -4953,12 +4953,11 @@ HTMLMediaElement::GetTopLevelPrincipal()
 {
   RefPtr<nsIPrincipal> principal;
   nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(OwnerDoc()->GetParentObject());
-  nsCOMPtr<nsIDOMWindow> topWindow;
   if (!window) {
     return nullptr;
   }
-  window->GetTop(getter_AddRefs(topWindow));
-  nsCOMPtr<nsPIDOMWindow> top = do_QueryInterface(topWindow);
+  window = window->GetOuterWindow();
+  nsCOMPtr<nsPIDOMWindow> top = window->GetTop();
   if (!top) {
     return nullptr;
   }
diff --git a/dom/html/nsGenericHTMLElement.cpp b/dom/html/nsGenericHTMLElement.cpp
index 1d9aaab05a0..84b827b1cda 100644
--- a/dom/html/nsGenericHTMLElement.cpp
+++ b/dom/html/nsGenericHTMLElement.cpp
@@ -132,10 +132,8 @@ public:
     }
 
     // Trying to found the top window (equivalent to window.top).
-    nsCOMPtr<nsIDOMWindow> top;
-    window->GetTop(getter_AddRefs(top));
-    if (top) {
-      window = static_cast<nsPIDOMWindow*>(top.get());
+    if (nsCOMPtr<nsPIDOMWindow> top = window->GetTop()) {
+      window = top;
     }
 
     if (window->GetFocusedNode()) {
diff --git a/dom/inputmethod/forms.js b/dom/inputmethod/forms.js
index 0510b08dce6..7da68641a66 100644
--- a/dom/inputmethod/forms.js
+++ b/dom/inputmethod/forms.js
@@ -261,7 +261,7 @@ var FormVisibility = {
     // we also care about the window this is the more
     // common case where the content is larger then
     // the viewport/screen.
-    if (win.scrollMaxX || win.scrollMaxY) {
+    if (win.scrollMaxX != win.scrollMinX || win.scrollMaxY != win.scrollMinY) {
       return win;
     }
 
diff --git a/dom/interfaces/base/nsIDOMWindow.idl b/dom/interfaces/base/nsIDOMWindow.idl
index dbf185ea274..b41458a1231 100644
--- a/dom/interfaces/base/nsIDOMWindow.idl
+++ b/dom/interfaces/base/nsIDOMWindow.idl
@@ -14,463 +14,17 @@ interface nsISelection;
 interface nsIVariant;
 
 /**
- * The nsIDOMWindow interface is the primary interface for a DOM
- * window object. It represents a single window object that may
- * contain child windows if the document in the window contains a
- * HTML frameset document or if the document contains iframe elements.
- *
- * @see <http://www.whatwg.org/html/#window>
+ * Empty interface for compatibility with older versions.
+ * @deprecated Use WebIDL for script visible features,
+ *             nsPIDOMWindow for C++ callers.
  */
 
-[scriptable, uuid(ab30b7cc-f7f9-4b9b-befb-7dbf6cf86d46)]
-interface nsIDOMWindow : nsISupports
-{
-  // the current browsing context
-  readonly attribute nsIDOMWindow                       window;
-
-  /* [replaceable] self */
-  readonly attribute nsIDOMWindow                       self;
-
-  /**
-   * Accessor for the document in this window.
-   */
-  readonly attribute nsIDOMDocument                     document;
-
-  /**
-   * Set/Get the name of this window.
-   *
-   * This attribute is "replaceable" in JavaScript
-   */
-           attribute DOMString                          name;
-
-  /* The setter that takes a string argument needs to be special cased! */
-  readonly attribute nsIDOMLocation                     location;
-
-  readonly attribute nsISupports                        history;
-
-
-  /* [replaceable] locationbar */
-  /* BarProp */
-  readonly attribute nsISupports                        locationbar;
-
-  /* [replaceable] menubar */
-  /* BarProp */
-  readonly attribute nsISupports                        menubar;
-
-  /* [replaceable] personalbar */
-  /* BarProp */
-  readonly attribute nsISupports                        personalbar;
-
-  /**
-   * Accessor for the object that controls whether or not scrollbars
-   * are shown in this window.
-   *
-   * This attribute is "replaceable" in JavaScript
-   */
-  /* BarProp */
-  readonly attribute nsISupports                        scrollbars;
-
-  /* [replaceable] statusbar */
-  /* BarProp */
-  readonly attribute nsISupports                        statusbar;
-
-  /* [replaceable] toolbar */
-  /* BarProp */
-  readonly attribute nsISupports                        toolbar;
-
-  /* [replaceable] */
-           attribute DOMString                          status;
-
-  void                      close();
-  void                      stop();
-  void                      focus();
-  void                      blur();
-
-
-  // other browsing contexts
-  /* [replaceable] length */
-  readonly attribute unsigned long                      length;
-
-  /**
-   * |top| gets the root of the window hierarchy.
-   *
-   * This function does not cross chrome-content boundaries, so if this
-   * window's parent is of a different type, |top| will return this window.
-   *
-   * When script reads the top property, we run GetScriptableTop, which
-   * will not cross an <iframe mozbrowser> boundary.
-   *
-   * In contrast, C++ calls to GetTop are forwarded to GetRealTop, which
-   * ignores <iframe mozbrowser> boundaries.
-   *
-   * This property is "replaceable" in JavaScript.
-   */
-  [binaryname(ScriptableTop)]
-  readonly attribute nsIDOMWindow                       top;
-
-  /**
-   * You shouldn't need to call this function directly; call GetTop instead.
-   */
-  [noscript]
-  readonly attribute nsIDOMWindow                       realTop;
-
-  %{C++
-  nsresult GetTop(nsIDOMWindow **aWindow)
-  {
-    return GetRealTop(aWindow);
-  }
-  %}
-
-  /**
-   * |parent| gets this window's parent window.  If this window has no parent,
-   * we return the window itself.
-   *
-   * This property does not cross chrome-content boundaries, so if this
-   * window's parent is of a different type, we return the window itself as its
-   * parent.
-   *
-   * When script reads the property (or when C++ calls ScriptableTop), this
-   * property does not cross <iframe mozbrowser> boundaries.  In contrast, when
-   * C++ calls GetParent, we ignore the mozbrowser attribute.
-   */
-  [binaryname(ScriptableParent)]
-  readonly attribute nsIDOMWindow                       parent;
-
-  /**
-   * You shouldn't need to read this property directly; call GetParent instead.
-   */
-  [noscript]
-  readonly attribute nsIDOMWindow                       realParent;
-
-  %{C++
-  inline nsresult GetParent(nsIDOMWindow **aWindow)
-  {
-    return GetRealParent(aWindow);
-  }
-  %}
-
-  [implicit_jscontext, binaryname(ScriptableOpener)]
-           attribute jsval                              opener;
-
-  [noscript, binaryname(Opener)]
-           attribute nsIDOMWindow                       openerWindow;
-
-  /**
-   * |frameElement| gets this window's <iframe> or <frame> element, if it has
-   * one.
-   *
-   * When script reads this property (or when C++ calls
-   * ScriptableFrameElement), we return |null| if the window is inside an
-   * <iframe mozbrowser>.  In contrast, when C++ calls GetFrameElement, we
-   * ignore the mozbrowser attribute.
-   */
-  [binaryname(ScriptableFrameElement)]
-  readonly attribute nsIDOMElement                      frameElement;
-
-  /**
-   * You shouldn't need to read this property directly; call GetFrameElement
-   * instead.
-   */
-  [noscript]
-  readonly attribute nsIDOMElement                      realFrameElement;
-
-  %{C++
-  inline nsresult GetFrameElement(nsIDOMElement **aElement)
-  {
-    return GetRealFrameElement(aElement);
-  }
-  %}
-
-
-  // the user agent
-  readonly attribute nsIDOMNavigator                    navigator;
-
-  /**
-   * Get the application cache object for this window.
-   */
-  readonly attribute nsIDOMOfflineResourceList          applicationCache;
-
-
-  // user prompts
-  void                      alert([optional, Null(Stringify)] in DOMString text);
-  boolean                   confirm([optional] in DOMString text);
-
-  // prompt() should return a null string if cancel is pressed
-  DOMString                 prompt([optional] in DOMString aMessage,
-                                   [optional] in DOMString aInitial);
-
-  void                      print();
-
-  [optional_argc]
-  nsIVariant                showModalDialog(in DOMString aURI,
-                                            [optional] in nsIVariant aArgs,
-                                            [optional] in DOMString aOptions);
-
-
-  // cross-document messaging
-  /**
-   * Implements a safe message-passing system which can cross same-origin
-   * boundaries.
-   *
-   * This method, when called, causes a MessageEvent to be asynchronously
-   * dispatched at the primary document for the window upon which this method is
-   * called.  (Note that the postMessage property on windows is allAccess and
-   * thus is readable cross-origin.)  The dispatched event will have message as
-   * its data, the calling context's window as its source, and an origin
-   * determined by the calling context's main document URI.  The targetOrigin
-   * argument specifies a URI and is used to restrict the message to be sent
-   * only when the target window has the same origin as targetOrigin (since,
-   * when the sender and the target have different origins, neither can read the
-   * location of the other).
-   * 
-   * @see <http://www.whatwg.org/html/#dom-window-postmessage>
-   */
-  [implicit_jscontext, binaryname(PostMessageMoz)]
-    void postMessage(in jsval message, in DOMString targetOrigin,
-                     [optional] in jsval transfer);
-
-
-  // WindowBase64
-  // Ascii base64 data to binary data and vice versa...
-  DOMString                 atob(in DOMString aAsciiString);
-  DOMString                 btoa(in DOMString aBase64Data);
-
-
-  // WindowSessionStorage
-  /**
-   * Session storage for the current browsing context.
-   * This attribute is a DOMStorage
-   */
-  readonly attribute nsISupports sessionStorage;
-
-
-  // WindowLocalStorage
-  /**
-   * Local storage for the current browsing context.
-   * This attribute is a DOMStorage
-   */
-  readonly attribute nsISupports localStorage;
-
-
-  // IndexedDB
-  // https://dvcs.w3.org/hg/IndexedDB/raw-file/tip/Overview.html#requests
-  // IDBEnvironment
-  readonly attribute nsISupports indexedDB;
-
-
-  // DOM Range
-  /**
-   * Method for accessing this window's selection object.
-   */
-  nsISelection              getSelection();
-
-
-  // CSSOM-View
-  // http://dev.w3.org/csswg/cssom-view/#extensions-to-the-window-interface
-  nsISupports      matchMedia(in DOMString media_query_list);
-
-  readonly attribute nsIDOMScreen                       screen;
-
-  // viewport
-           attribute long                               innerWidth;
-           attribute long                               innerHeight;
-
-
-  // viewport scrolling
-  /**
-   * Accessor for the current x scroll position in this window in
-   * pixels.
-   *
-   * This attribute is "replaceable" in JavaScript
-   */
-  readonly attribute long                               scrollX;
-
-  /* The offset in pixels by which the window is scrolled */
-  readonly attribute long                               pageXOffset;
-
-  /**
-   * Accessor for the current y scroll position in this window in
-   * pixels.
-   *
-   * This attribute is "replaceable" in JavaScript
-   */
-  readonly attribute long                               scrollY;
-
-  /* The offset in pixels by which the window is scrolled */
-  readonly attribute long                               pageYOffset;
-
-  void                      scroll(in long xScroll, in long yScroll);
-
-  /**
-   * Method for scrolling this window to an absolute pixel offset.
-   */
-  void                      scrollTo(in long xScroll, in long yScroll);
-
-  /**
-   * Method for scrolling this window to a pixel offset relative to
-   * the current scroll position.
-   */
-  void                      scrollBy(in long xScrollDif, in long yScrollDif);
-
-
-  // client
-           attribute long                        screenX;
-           attribute long                        screenY;
-           attribute long                        outerWidth;
-           attribute long                        outerHeight;
-
-
-  // CSSOM
-  /**
-   * @see <http://dev.w3.org/csswg/cssom/#dom-window-getcomputedstyle>
-   */
-  nsIDOMCSSStyleDeclaration getComputedStyle(in nsIDOMElement elt, 
-                                             [optional] in DOMString pseudoElt);
-  nsIDOMCSSStyleDeclaration getDefaultComputedStyle(in nsIDOMElement elt,
-                                                    [optional] in DOMString pseudoElt);
-
-
-  // Mozilla extensions
-  /**
-   * Get the window root for this window. This is useful for hooking
-   * up event listeners to this window and every other window nested
-   * in the window root.
-   */
-  [noscript] readonly attribute nsIDOMEventTarget windowRoot;
-
-  /**
-   * Accessor for the child windows in this window.
-   */
-  [noscript] readonly attribute nsIDOMWindowCollection  frames;
-
-  /**
-   * Set/Get the document scale factor as a multiplier on the default
-   * size. When setting this attribute, a NS_ERROR_NOT_IMPLEMENTED
-   * error may be returned by implementations not supporting
-   * zoom. Implementations not supporting zoom should return 1.0 all
-   * the time for the Get operation. 1.0 is equals normal size,
-   * i.e. no zoom.
-   */
-  [noscript] attribute float                            textZoom;
-
-  /**
-   * Method for scrolling this window by a number of lines.
-   */
-  void                      scrollByLines(in long numLines);
-
-  /**
-   * Method for scrolling this window by a number of pages.
-   */
-  void                      scrollByPages(in long numPages);
-
-  /**
-   * Method for sizing this window to the content in the window.
-   */
-  void                      sizeToContent();
-
-  /* [replaceable] prompter */
-  [noscript] readonly attribute nsIPrompt               prompter;
-
-  readonly attribute boolean                            closed;
-
-  readonly attribute nsIDOMCrypto                       crypto;
-
-  // Note: this is [ChromeOnly] scriptable via WebIDL.
-  [noscript] readonly attribute nsIControllers          controllers;
-
-  readonly attribute float                              mozInnerScreenX;
-  readonly attribute float                              mozInnerScreenY;
-  readonly attribute float                              devicePixelRatio;
-
-  /* The maximum offset that the window can be scrolled to
-     (i.e., the document width/height minus the scrollport width/height) */
-  readonly attribute long                               scrollMaxX;
-  readonly attribute long                               scrollMaxY;
-
-           attribute boolean                            fullScreen;
-
-  void                      back();
-  void                      forward();
-  void                      home();
-
-  void                      moveTo(in long xPos, in long yPos);
-  void                      moveBy(in long xDif, in long yDif);
-  void                      resizeTo(in long width, in long height);
-  void                      resizeBy(in long widthDif, in long heightDif);
-
-  /**
-   * Open a new window with this one as the parent.  This method will
-   * NOT examine the JS stack for purposes of determining a caller.
-   * This window will be used for security checks during the search by
-   * name and the default character set on the newly opened window
-   * will just be the default character set of this window.
-   */
-  [noscript] nsIDOMWindow   open(in DOMString url, in DOMString name,
-                                 in DOMString options);
-
-  /**
-   * This method works like open except that aExtraArgument gets
-   * converted into the array window.arguments in JS, if
-   * aExtraArgument is a nsISupportsArray then the individual items in
-   * the array are inserted into window.arguments, and primitive
-   * nsISupports (nsISupportsPrimitives) types are converted to native
-   * JS types when possible.
-   */
-  [noscript] nsIDOMWindow   openDialog(in DOMString url, in DOMString name,
-                                       in DOMString options,
-                                       in nsISupports aExtraArgument);
-
-  // XXX Should this be in nsIDOMChromeWindow?
-  void                      updateCommands(in DOMString action,
-                                           [optional] in nsISelection sel,
-                                           [optional] in short reason);
-
-  /* Find in page.
-   * @param str: the search pattern
-   * @param caseSensitive: is the search caseSensitive
-   * @param backwards: should we search backwards
-   * @param wrapAround: should we wrap the search
-   * @param wholeWord: should we search only for whole words
-   * @param searchInFrames: should we search through all frames
-   * @param showDialog: should we show the Find dialog
-   */
-  boolean                   find([optional] in DOMString str,
-                                 [optional] in boolean caseSensitive,
-                                 [optional] in boolean backwards,
-                                 [optional] in boolean wrapAround,
-                                 [optional] in boolean wholeWord,
-                                 [optional] in boolean searchInFrames,
-                                 [optional] in boolean showDialog);
-
-  /**
-   * Returns the number of times this document for this window has
-   * been painted to the screen.
-   */
-  readonly attribute unsigned long long mozPaintCount;
-
-  /**
-   * Request a refresh of this browser window.
-   *
-   * @see <http://dvcs.w3.org/hg/webperf/raw-file/tip/specs/RequestAnimationFrame/Overview.html>
-   */
-  // jsval because we want a WebIDL callback here
-  [implicit_jscontext]
-  long requestAnimationFrame(in jsval aCallback);
-
-  /**
-   * Cancel a refresh callback.
-   */
-  void cancelAnimationFrame(in long aHandle);
-
-  /**
-   * Console API
-   */
-  [implicit_jscontext] attribute jsval console;
-};
+[scriptable, uuid(b8343993-0383-4add-9930-ad176b189240)]
+interface nsIDOMWindow : nsISupports {};
 
 /**
  * Empty interface for compatibility with older versions.
  * @deprecated Use nsIDOMWindow instead
  */
-[scriptable, uuid(2ec49e81-b2ba-4633-991a-f48f1e1d8800)]
+[scriptable, uuid(8c589e65-3237-4cd1-8bad-c5c47135e79b)]
 interface nsIDOMWindowInternal : nsIDOMWindow {};
diff --git a/dom/ipc/TabChild.cpp b/dom/ipc/TabChild.cpp
index f4bceb5a274..6aa5bc884a4 100644
--- a/dom/ipc/TabChild.cpp
+++ b/dom/ipc/TabChild.cpp
@@ -1191,20 +1191,8 @@ TabChild::ProvideWindowCommon(nsIDOMWindow* aOpener,
                                          NS_ConvertUTF8toUTF16(features),
                                          aWindowIsNew);
   } else {
-    nsCOMPtr<nsIDOMDocument> domDoc;
-    aOpener->GetDocument(getter_AddRefs(domDoc));
-    if (!domDoc) {
-      NS_ERROR("Could retrieve document from nsIBaseWindow");
-      return NS_ERROR_FAILURE;
-    }
-
-    nsCOMPtr<nsIDocument> doc;
-    doc = do_QueryInterface(domDoc);
-    if (!doc) {
-      NS_ERROR("Document from nsIBaseWindow didn't QI to nsIDocument");
-      return NS_ERROR_FAILURE;
-    }
-
+    nsCOMPtr<nsPIDOMWindow> opener = do_QueryInterface(aOpener);
+    nsCOMPtr<nsIDocument> doc = opener->GetDoc();
     nsCOMPtr<nsIURI> baseURI = doc->GetDocBaseURI();
     if (!baseURI) {
       NS_ERROR("nsIDocument didn't return a base URI");
diff --git a/dom/ipc/TabParent.cpp b/dom/ipc/TabParent.cpp
index 0cbaa953be7..5801b551457 100644
--- a/dom/ipc/TabParent.cpp
+++ b/dom/ipc/TabParent.cpp
@@ -755,7 +755,7 @@ private:
   nsCString* mURLToLoad;
 };
 
-static already_AddRefed<nsIDOMWindow>
+static already_AddRefed<nsPIDOMWindow>
 FindMostRecentOpenWindow()
 {
   nsCOMPtr<nsIWindowMediator> windowMediator =
@@ -764,17 +764,16 @@ FindMostRecentOpenWindow()
   windowMediator->GetEnumerator(MOZ_UTF16("navigator:browser"),
                                 getter_AddRefs(windowEnumerator));
 
-  nsCOMPtr<nsIDOMWindow> latest;
+  nsCOMPtr<nsPIDOMWindow> latest;
 
   bool hasMore = false;
   MOZ_ALWAYS_TRUE(NS_SUCCEEDED(windowEnumerator->HasMoreElements(&hasMore)));
   while (hasMore) {
     nsCOMPtr<nsISupports> item;
     MOZ_ALWAYS_TRUE(NS_SUCCEEDED(windowEnumerator->GetNext(getter_AddRefs(item))));
-    nsCOMPtr<nsIDOMWindow> window = do_QueryInterface(item);
+    nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(item);
 
-    bool isClosed;
-    if (window && NS_SUCCEEDED(window->GetClosed(&isClosed)) && !isClosed) {
+    if (window && !window->Closed()) {
       latest = window;
     }
 
@@ -827,17 +826,14 @@ TabParent::RecvCreateWindow(PBrowserParent* aNewTab,
 
   nsCOMPtr<nsIContent> frame(do_QueryInterface(mFrameElement));
 
-  nsCOMPtr<nsIDOMWindow> parent;
+  nsCOMPtr<nsPIDOMWindow> parent;
   if (frame) {
-    parent = do_QueryInterface(frame->OwnerDoc()->GetWindow());
+    parent = frame->OwnerDoc()->GetWindow();
 
     // If our chrome window is in the process of closing, don't try to open a
     // new tab in it.
-    if (parent) {
-      bool isClosed;
-      if (NS_SUCCEEDED(parent->GetClosed(&isClosed)) && isClosed) {
-        parent = nullptr;
-      }
+    if (parent && parent->Closed()) {
+      parent = nullptr;
     }
   }
 
diff --git a/dom/media/BufferMediaResource.h b/dom/media/BufferMediaResource.h
index ffe09a7fcf4..82ff184fdf1 100644
--- a/dom/media/BufferMediaResource.h
+++ b/dom/media/BufferMediaResource.h
@@ -50,7 +50,7 @@ private:
     return principal.forget();
   }
   virtual bool CanClone() override { return false; }
-  virtual already_AddRefed<MediaResource> CloneData(MediaDecoder* aDecoder) override
+  virtual already_AddRefed<MediaResource> CloneData(MediaResourceCallback*) override
   {
     return nullptr;
   }
diff --git a/dom/media/MediaDecoder.cpp b/dom/media/MediaDecoder.cpp
index 8ec78cd11c2..c7296c57d4b 100644
--- a/dom/media/MediaDecoder.cpp
+++ b/dom/media/MediaDecoder.cpp
@@ -716,6 +716,50 @@ MediaDecoder::FirstFrameLoaded(nsAutoPtr<MediaInfo> aInfo,
   NotifySuspendedStatusChanged();
 }
 
+nsresult
+MediaDecoder::FinishDecoderSetup(MediaResource* aResource)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  HTMLMediaElement* element = mOwner->GetMediaElement();
+  NS_ENSURE_TRUE(element, NS_ERROR_FAILURE);
+  element->FinishDecoderSetup(this, aResource);
+  return NS_OK;
+}
+
+void
+MediaDecoder::NotifyNetworkError()
+{
+  NetworkError();
+}
+
+void
+MediaDecoder::NotifyDecodeError()
+{
+  nsCOMPtr<nsIRunnable> r =
+    NS_NewRunnableMethod(this, &MediaDecoder::DecodeError);
+  AbstractThread::MainThread()->Dispatch(r.forget());
+}
+
+void
+MediaDecoder::NotifyDataEnded(nsresult aStatus)
+{
+  RefPtr<MediaDecoder> self = this;
+  nsCOMPtr<nsIRunnable> r = NS_NewRunnableFunction([=] () {
+    self->NotifyDownloadEnded(aStatus);
+    if (NS_SUCCEEDED(aStatus)) {
+      HTMLMediaElement* element = self->mOwner->GetMediaElement();
+      if (element) {
+        element->DownloadSuspended();
+      }
+      // NotifySuspendedStatusChanged will tell the element that download
+      // has been suspended "by the cache", which is true since we never
+      // download anything. The element can then transition to HAVE_ENOUGH_DATA.
+      self->NotifySuspendedStatusChanged();
+    }
+  });
+  AbstractThread::MainThread()->Dispatch(r.forget());
+}
+
 void
 MediaDecoder::ResetConnectionState()
 {
@@ -927,6 +971,13 @@ MediaDecoder::NotifyPrincipalChanged()
 void
 MediaDecoder::NotifyBytesConsumed(int64_t aBytes, int64_t aOffset)
 {
+  if (!NS_IsMainThread()) {
+    nsCOMPtr<nsIRunnable> r = NS_NewRunnableMethodWithArgs<int64_t, int64_t>(
+      this, &MediaDecoder::NotifyBytesConsumed, aBytes, aOffset);
+    AbstractThread::MainThread()->Dispatch(r.forget());
+    return;
+  }
+
   MOZ_ASSERT(NS_IsMainThread());
 
   if (mShuttingDown || mIgnoreProgressData) {
diff --git a/dom/media/MediaDecoder.h b/dom/media/MediaDecoder.h
index 06858e50d0b..8ccc792ccc7 100644
--- a/dom/media/MediaDecoder.h
+++ b/dom/media/MediaDecoder.h
@@ -209,6 +209,7 @@ destroying the MediaDecoder object.
 #include "MediaEventSource.h"
 #include "MediaMetadataManager.h"
 #include "MediaResource.h"
+#include "MediaResourceCallback.h"
 #include "MediaStatistics.h"
 #include "MediaStreamGraph.h"
 #include "TimeUnits.h"
@@ -272,7 +273,7 @@ struct SeekTarget {
   MediaDecoderEventVisibility mEventVisibility;
 };
 
-class MediaDecoder : public AbstractMediaDecoder
+class MediaDecoder : public AbstractMediaDecoder, public MediaResourceCallback
 {
 public:
   struct SeekResolveValue {
@@ -303,7 +304,7 @@ public:
 
   // Reset the decoder and notify the media element that
   // server connection is closed.
-  virtual void ResetConnectionState();
+  virtual void ResetConnectionState() override;
   // Create a new decoder of the same type as this one.
   // Subclasses must implement this.
   virtual MediaDecoder* Clone(MediaDecoderOwner* aOwner) = 0;
@@ -410,7 +411,7 @@ public:
   //
   // When the media stream ends, we can know the duration, thus the stream is
   // no longer considered to be infinite.
-  virtual void SetInfinite(bool aInfinite);
+  virtual void SetInfinite(bool aInfinite) override;
 
   // Return true if the stream is infinite (see SetInfinite).
   virtual bool IsInfinite();
@@ -419,11 +420,11 @@ public:
   // If MediaResource::IsSuspendedByCache returns true, then the decoder
   // should stop buffering or otherwise waiting for download progress and
   // start consuming data, if possible, because the cache is full.
-  virtual void NotifySuspendedStatusChanged();
+  virtual void NotifySuspendedStatusChanged() override;
 
   // Called by MediaResource when some data has been received.
   // Call on the main thread only.
-  virtual void NotifyBytesDownloaded();
+  virtual void NotifyBytesDownloaded() override;
 
   // Called by nsChannelToPipeListener or MediaResource when the
   // download has ended. Called on the main thread only. aStatus is
@@ -437,7 +438,7 @@ public:
 
   // Called by MediaResource when the principal of the resource has
   // changed. Called on main thread only.
-  virtual void NotifyPrincipalChanged();
+  virtual void NotifyPrincipalChanged() override;
 
   // Called by the MediaResource to keep track of the number of bytes read
   // from the resource. Called on the main by an event runner dispatched
@@ -509,7 +510,7 @@ public:
   void SetLoadInBackground(bool aLoadInBackground);
 
   // Returns a weak reference to the media decoder owner.
-  MediaDecoderOwner* GetMediaOwner() const;
+  MediaDecoderOwner* GetMediaOwner() const override;
 
   bool OnStateMachineTaskQueue() const override;
 
@@ -1054,6 +1055,13 @@ public:
   AbstractCanonical<bool>* CanonicalMediaSeekable() {
     return &mMediaSeekable;
   }
+
+private:
+  /* MediaResourceCallback functions */
+  virtual nsresult FinishDecoderSetup(MediaResource* aResource) override;
+  virtual void NotifyNetworkError() override;
+  virtual void NotifyDecodeError() override;
+  virtual void NotifyDataEnded(nsresult aStatus) override;
 };
 
 } // namespace mozilla
diff --git a/dom/media/MediaResource.cpp b/dom/media/MediaResource.cpp
index 0395c50c5b3..74298e910b7 100644
--- a/dom/media/MediaResource.cpp
+++ b/dom/media/MediaResource.cpp
@@ -7,11 +7,11 @@
 #include "mozilla/DebugOnly.h"
 
 #include "MediaResource.h"
+#include "MediaResourceCallback.h"
 #include "RtspMediaResource.h"
 
 #include "mozilla/Mutex.h"
 #include "nsDebug.h"
-#include "MediaDecoder.h"
 #include "nsNetUtil.h"
 #include "nsThreadUtils.h"
 #include "nsIFile.h"
@@ -65,11 +65,11 @@ NS_IMPL_ADDREF(MediaResource)
 NS_IMPL_RELEASE_WITH_DESTROY(MediaResource, Destroy())
 NS_IMPL_QUERY_INTERFACE0(MediaResource)
 
-ChannelMediaResource::ChannelMediaResource(MediaDecoder* aDecoder,
+ChannelMediaResource::ChannelMediaResource(MediaResourceCallback* aCallback,
                                            nsIChannel* aChannel,
                                            nsIURI* aURI,
                                            const nsACString& aContentType)
-  : BaseMediaResource(aDecoder, aChannel, aURI, aContentType),
+  : BaseMediaResource(aCallback, aChannel, aURI, aContentType),
     mOffset(0),
     mReopenOnError(false),
     mIgnoreClose(false),
@@ -161,7 +161,7 @@ ChannelMediaResource::OnStartRequest(nsIRequest* aRequest)
 {
   NS_ASSERTION(mChannel.get() == aRequest, "Wrong channel!");
 
-  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
+  MediaDecoderOwner* owner = mCallback->GetMediaOwner();
   NS_ENSURE_TRUE(owner, NS_ERROR_FAILURE);
   dom::HTMLMediaElement* element = owner->GetMediaElement();
   NS_ENSURE_TRUE(element, NS_ERROR_FAILURE);
@@ -183,7 +183,7 @@ ChannelMediaResource::OnStartRequest(nsIRequest* aRequest)
     // If the request was cancelled by nsCORSListenerProxy due to failing
     // the CORS security check, send an error through to the media element.
     if (status == NS_ERROR_DOM_BAD_URI) {
-      mDecoder->NetworkError();
+      mCallback->NotifyNetworkError();
       return NS_ERROR_DOM_BAD_URI;
     }
   }
@@ -211,7 +211,7 @@ ChannelMediaResource::OnStartRequest(nsIRequest* aRequest)
         // work here.
         mCacheStream.NotifyDataEnded(status);
       } else {
-        mDecoder->NetworkError();
+        mCallback->NotifyNetworkError();
       }
 
       // This disconnects our listener so we don't get any more data. We
@@ -249,8 +249,8 @@ ChannelMediaResource::OnStartRequest(nsIRequest* aRequest)
         // Content-Range header text should be parse-able.
         CMLOG("Error processing \'Content-Range' for "
               "HTTP_PARTIAL_RESPONSE_CODE: rv[%x] channel[%p] decoder[%p]",
-              rv, hc.get(), mDecoder);
-        mDecoder->NetworkError();
+              rv, hc.get(), mCallback);
+        mCallback->NotifyNetworkError();
         CloseChannel();
         return NS_OK;
       }
@@ -307,7 +307,7 @@ ChannelMediaResource::OnStartRequest(nsIRequest* aRequest)
       dataIsBounded = true;
     }
 
-    mDecoder->SetInfinite(!dataIsBounded);
+    mCallback->SetInfinite(!dataIsBounded);
   }
   mCacheStream.SetTransportSeekable(seekable);
 
@@ -377,7 +377,7 @@ ChannelMediaResource::ParseContentRangeHeader(nsIHttpChannel * aHttpChan,
   }
 
   CMLOG("Received bytes [%lld] to [%lld] of [%lld] for decoder[%p]",
-        aRangeStart, aRangeEnd, aRangeTotal, mDecoder);
+        aRangeStart, aRangeEnd, aRangeTotal, mCallback);
 
   return NS_OK;
 }
@@ -455,14 +455,14 @@ ChannelMediaResource::CopySegmentToCache(nsIInputStream *aInStream,
 {
   CopySegmentClosure* closure = static_cast<CopySegmentClosure*>(aClosure);
 
-  closure->mResource->mDecoder->NotifyDataArrived(aCount, closure->mResource->mOffset,
+  closure->mResource->mCallback->NotifyDataArrived(aCount, closure->mResource->mOffset,
                                                   /* aThrottleUpdates = */ true);
 
   // Keep track of where we're up to.
   RESOURCE_LOG("%p [ChannelMediaResource]: CopySegmentToCache at mOffset [%lld] add "
                "[%d] bytes for decoder[%p]",
                closure->mResource, closure->mResource->mOffset, aCount,
-               closure->mResource->mDecoder);
+               closure->mResource->mCallback);
   closure->mResource->mOffset += aCount;
 
   closure->mResource->mCacheStream.NotifyDataReceived(aCount, aFromSegment,
@@ -569,7 +569,7 @@ nsresult ChannelMediaResource::OpenChannel(nsIStreamListener** aStreamListener)
     NS_ENSURE_SUCCESS(rv, rv);
 
     // Tell the media element that we are fetching data from a channel.
-    MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
+    MediaDecoderOwner* owner = mCallback->GetMediaOwner();
     NS_ENSURE_TRUE(owner, NS_ERROR_FAILURE);
     dom::HTMLMediaElement* element = owner->GetMediaElement();
     element->DownloadResumed(true);
@@ -604,7 +604,7 @@ nsresult ChannelMediaResource::SetupChannelHeaders()
 
     // Send Accept header for video and audio types only (Bug 489071)
     NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");
-    MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
+    MediaDecoderOwner* owner = mCallback->GetMediaOwner();
     NS_ENSURE_TRUE(owner, NS_ERROR_FAILURE);
     dom::HTMLMediaElement* element = owner->GetMediaElement();
     NS_ENSURE_TRUE(element, NS_ERROR_FAILURE);
@@ -638,13 +638,13 @@ bool ChannelMediaResource::CanClone()
   return mCacheStream.IsAvailableForSharing();
 }
 
-already_AddRefed<MediaResource> ChannelMediaResource::CloneData(MediaDecoder* aDecoder)
+already_AddRefed<MediaResource> ChannelMediaResource::CloneData(MediaResourceCallback* aCallback)
 {
   NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
   NS_ASSERTION(mCacheStream.IsAvailableForSharing(), "Stream can't be cloned");
 
   RefPtr<ChannelMediaResource> resource =
-    new ChannelMediaResource(aDecoder,
+    new ChannelMediaResource(aCallback,
                              nullptr,
                              mURI,
                              GetContentType());
@@ -753,7 +753,7 @@ void ChannelMediaResource::Suspend(bool aCloseImmediately)
 {
   NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");
 
-  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
+  MediaDecoderOwner* owner = mCallback->GetMediaOwner();
   if (!owner) {
     // Shutting down; do nothing.
     return;
@@ -786,7 +786,7 @@ void ChannelMediaResource::Resume()
 {
   NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");
 
-  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
+  MediaDecoderOwner* owner = mCallback->GetMediaOwner();
   if (!owner) {
     // Shutting down; do nothing.
     return;
@@ -835,7 +835,7 @@ ChannelMediaResource::RecreateChannel()
     nsICachingChannel::LOAD_BYPASS_LOCAL_CACHE_IF_BUSY |
     (mLoadInBackground ? nsIRequest::LOAD_BACKGROUND : 0);
 
-  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
+  MediaDecoderOwner* owner = mCallback->GetMediaOwner();
   if (!owner) {
     // The decoder is being shut down, so don't bother opening a new channel
     return NS_OK;
@@ -885,7 +885,7 @@ void
 ChannelMediaResource::DoNotifyDataReceived()
 {
   mDataReceivedEvent.Revoke();
-  mDecoder->NotifyBytesDownloaded();
+  mCallback->NotifyBytesDownloaded();
 }
 
 void
@@ -903,41 +903,11 @@ ChannelMediaResource::CacheClientNotifyDataReceived()
   NS_DispatchToMainThread(mDataReceivedEvent.get());
 }
 
-class DataEnded : public nsRunnable {
-public:
-  DataEnded(MediaDecoder* aDecoder, nsresult aStatus) :
-    mDecoder(aDecoder), mStatus(aStatus) {}
-  NS_IMETHOD Run() {
-    mDecoder->NotifyDownloadEnded(mStatus);
-    if (NS_SUCCEEDED(mStatus)) {
-      MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
-      if (owner) {
-        dom::HTMLMediaElement* element = owner->GetMediaElement();
-        if (element) {
-          element->DownloadSuspended();
-        }
-      }
-      // NotifySuspendedStatusChanged will tell the element that download
-      // has been suspended "by the cache", which is true since we never download
-      // anything. The element can then transition to HAVE_ENOUGH_DATA.
-      mDecoder->NotifySuspendedStatusChanged();
-    }
-    return NS_OK;
-  }
-private:
-  RefPtr<MediaDecoder> mDecoder;
-  nsresult               mStatus;
-};
-
 void
 ChannelMediaResource::CacheClientNotifyDataEnded(nsresult aStatus)
 {
   MOZ_ASSERT(NS_IsMainThread());
-  // NOTE: this can be called with the media cache lock held, so don't
-  // block or do anything which might try to acquire a lock!
-
-  nsCOMPtr<nsIRunnable> event = new DataEnded(mDecoder, aStatus);
-  NS_DispatchToCurrentThread(event);
+  mCallback->NotifyDataEnded(aStatus);
 }
 
 void
@@ -945,14 +915,14 @@ ChannelMediaResource::CacheClientNotifyPrincipalChanged()
 {
   NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");
 
-  mDecoder->NotifyPrincipalChanged();
+  mCallback->NotifyPrincipalChanged();
 }
 
 void
 ChannelMediaResource::CacheClientNotifySuspendedStatusChanged()
 {
   NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");
-  mDecoder->NotifySuspendedStatusChanged();
+  mCallback->NotifySuspendedStatusChanged();
 }
 
 nsresult
@@ -961,7 +931,7 @@ ChannelMediaResource::CacheClientSeek(int64_t aOffset, bool aResume)
   NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");
 
   CMLOG("CacheClientSeek requested for aOffset [%lld] for decoder [%p]",
-        aOffset, mDecoder);
+        aOffset, mCallback);
 
   CloseChannel();
 
@@ -1171,11 +1141,11 @@ ChannelSuspendAgent::IsSuspended()
 class FileMediaResource : public BaseMediaResource
 {
 public:
-  FileMediaResource(MediaDecoder* aDecoder,
+  FileMediaResource(MediaResourceCallback* aCallback,
                     nsIChannel* aChannel,
                     nsIURI* aURI,
                     const nsACString& aContentType) :
-    BaseMediaResource(aDecoder, aChannel, aURI, aContentType),
+    BaseMediaResource(aCallback, aChannel, aURI, aContentType),
     mSize(-1),
     mLock("FileMediaResource.mLock"),
     mSizeInitialized(false)
@@ -1192,7 +1162,7 @@ public:
   virtual void     Resume() override {}
   virtual already_AddRefed<nsIPrincipal> GetCurrentPrincipal() override;
   virtual bool     CanClone() override;
-  virtual already_AddRefed<MediaResource> CloneData(MediaDecoder* aDecoder) override;
+  virtual already_AddRefed<MediaResource> CloneData(MediaResourceCallback* aCallback) override;
   virtual nsresult ReadFromCache(char* aBuffer, int64_t aOffset, uint32_t aCount) override;
 
   // These methods are called off the main thread.
@@ -1306,8 +1276,7 @@ void FileMediaResource::EnsureSizeInitialized()
   nsresult res = mInput->Available(&size);
   if (NS_SUCCEEDED(res) && size <= INT64_MAX) {
     mSize = (int64_t)size;
-    nsCOMPtr<nsIRunnable> event = new DataEnded(mDecoder, NS_OK);
-    NS_DispatchToMainThread(event);
+    mCallback->NotifyDataEnded(NS_OK);
   }
 }
 
@@ -1404,11 +1373,11 @@ bool FileMediaResource::CanClone()
   return true;
 }
 
-already_AddRefed<MediaResource> FileMediaResource::CloneData(MediaDecoder* aDecoder)
+already_AddRefed<MediaResource> FileMediaResource::CloneData(MediaResourceCallback* aCallback)
 {
   NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
 
-  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
+  MediaDecoderOwner* owner = mCallback->GetMediaOwner();
   if (!owner) {
     // The decoder is being shut down, so we can't clone
     return nullptr;
@@ -1441,7 +1410,7 @@ already_AddRefed<MediaResource> FileMediaResource::CloneData(MediaDecoder* aDeco
   if (NS_FAILED(rv))
     return nullptr;
 
-  RefPtr<MediaResource> resource(new FileMediaResource(aDecoder, channel, mURI, GetContentType()));
+  RefPtr<MediaResource> resource(new FileMediaResource(aCallback, channel, mURI, GetContentType()));
   return resource.forget();
 }
 
@@ -1562,7 +1531,7 @@ int64_t FileMediaResource::Tell()
 }
 
 already_AddRefed<MediaResource>
-MediaResource::Create(MediaDecoder* aDecoder, nsIChannel* aChannel)
+MediaResource::Create(MediaResourceCallback* aCallback, nsIChannel* aChannel)
 {
   NS_ASSERTION(NS_IsMainThread(),
                "MediaResource::Open called on non-main thread");
@@ -1580,11 +1549,11 @@ MediaResource::Create(MediaDecoder* aDecoder, nsIChannel* aChannel)
   nsCOMPtr<nsIFileChannel> fc = do_QueryInterface(aChannel);
   RefPtr<MediaResource> resource;
   if (fc || IsBlobURI(uri)) {
-    resource = new FileMediaResource(aDecoder, aChannel, uri, contentType);
+    resource = new FileMediaResource(aCallback, aChannel, uri, contentType);
   } else if (IsRtspURI(uri)) {
-    resource = new RtspMediaResource(aDecoder, aChannel, uri, contentType);
+    resource = new RtspMediaResource(aCallback, aChannel, uri, contentType);
   } else {
-    resource = new ChannelMediaResource(aDecoder, aChannel, uri, contentType);
+    resource = new ChannelMediaResource(aCallback, aChannel, uri, contentType);
   }
   return resource.forget();
 }
@@ -1599,7 +1568,7 @@ void BaseMediaResource::SetLoadInBackground(bool aLoadInBackground) {
     return;
   }
 
-  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
+  MediaDecoderOwner* owner = mCallback->GetMediaOwner();
   if (!owner) {
     NS_WARNING("Null owner in MediaResource::SetLoadInBackground()");
     return;
@@ -1652,45 +1621,12 @@ void BaseMediaResource::ModifyLoadFlags(nsLoadFlags aFlags)
   }
 }
 
-class DispatchBytesConsumedEvent : public nsRunnable {
-public:
-  DispatchBytesConsumedEvent(MediaDecoder* aDecoder,
-                             int64_t aNumBytes,
-                             int64_t aOffset)
-    : mDecoder(aDecoder),
-      mNumBytes(aNumBytes),
-      mOffset(aOffset)
-  {
-    MOZ_COUNT_CTOR(DispatchBytesConsumedEvent);
-  }
-
-protected:
-  ~DispatchBytesConsumedEvent()
-  {
-    MOZ_COUNT_DTOR(DispatchBytesConsumedEvent);
-  }
-
-public:
-  NS_IMETHOD Run() {
-    mDecoder->NotifyBytesConsumed(mNumBytes, mOffset);
-    // Drop ref to decoder on main thread, just in case this reference
-    // ends up being the last owning reference somehow.
-    mDecoder = nullptr;
-    return NS_OK;
-  }
-
-  RefPtr<MediaDecoder> mDecoder;
-  int64_t mNumBytes;
-  int64_t mOffset;
-};
-
 void BaseMediaResource::DispatchBytesConsumed(int64_t aNumBytes, int64_t aOffset)
 {
   if (aNumBytes <= 0) {
     return;
   }
-  RefPtr<nsIRunnable> event(new DispatchBytesConsumedEvent(mDecoder, aNumBytes, aOffset));
-  NS_DispatchToMainThread(event);
+  mCallback->NotifyBytesConsumed(aNumBytes, aOffset);
 }
 
 nsresult
diff --git a/dom/media/MediaResource.h b/dom/media/MediaResource.h
index f179e798100..88751746a6d 100644
--- a/dom/media/MediaResource.h
+++ b/dom/media/MediaResource.h
@@ -43,7 +43,7 @@ class nsIPrincipal;
 
 namespace mozilla {
 
-class MediaDecoder;
+class MediaResourceCallback;
 class MediaChannelStatistics;
 
 /**
@@ -270,7 +270,7 @@ public:
   // Create a new stream of the same type that refers to the same URI
   // with a new channel. Any cached data associated with the original
   // stream should be accessible in the new stream too.
-  virtual already_AddRefed<MediaResource> CloneData(MediaDecoder* aDecoder) = 0;
+  virtual already_AddRefed<MediaResource> CloneData(MediaResourceCallback* aCallback) = 0;
   // Set statistics to be recorded to the object passed in.
   virtual void RecordStatisticsTo(MediaChannelStatistics *aStatistics) { }
 
@@ -387,7 +387,7 @@ public:
    * Create a resource, reading data from the channel. Call on main thread only.
    * The caller must follow up by calling resource->Open().
    */
-  static already_AddRefed<MediaResource> Create(MediaDecoder* aDecoder, nsIChannel* aChannel);
+  static already_AddRefed<MediaResource> Create(MediaResourceCallback* aCallback, nsIChannel* aChannel);
 
   /**
    * Open the stream. This creates a stream listener and returns it in
@@ -460,7 +460,7 @@ public:
     // - mChannel
     // - mURI (possibly owned, looks like just a ref from mChannel)
     // Not owned:
-    // - mDecoder
+    // - mCallback
     size_t size = MediaResource::SizeOfExcludingThis(aMallocSizeOf);
     size += mContentType.SizeOfExcludingThisIfUnshared(aMallocSizeOf);
 
@@ -480,11 +480,11 @@ public:
   }
 
 protected:
-  BaseMediaResource(MediaDecoder* aDecoder,
+  BaseMediaResource(MediaResourceCallback* aCallback,
                     nsIChannel* aChannel,
                     nsIURI* aURI,
                     const nsACString& aContentType) :
-    mDecoder(aDecoder),
+    mCallback(aCallback),
     mChannel(aChannel),
     mURI(aURI),
     mContentType(aContentType),
@@ -516,7 +516,7 @@ protected:
   // This is not an nsCOMPointer to prevent a circular reference
   // between the decoder to the media stream object. The stream never
   // outlives the lifetime of the decoder.
-  MediaDecoder* mDecoder;
+  MediaResourceCallback* mCallback;
 
   // Channel used to download the media data. Must be accessed
   // from the main thread only.
@@ -593,7 +593,7 @@ private:
 class ChannelMediaResource : public BaseMediaResource
 {
 public:
-  ChannelMediaResource(MediaDecoder* aDecoder,
+  ChannelMediaResource(MediaResourceCallback* aDecoder,
                        nsIChannel* aChannel,
                        nsIURI* aURI,
                        const nsACString& aContentType);
@@ -643,7 +643,7 @@ public:
   // Return true if the stream has been closed.
   bool IsClosed() const { return mCacheStream.IsClosed(); }
   virtual bool     CanClone() override;
-  virtual already_AddRefed<MediaResource> CloneData(MediaDecoder* aDecoder) override;
+  virtual already_AddRefed<MediaResource> CloneData(MediaResourceCallback* aDecoder) override;
   // Set statistics to be recorded to the object passed in. If not called,
   // |ChannelMediaResource| will create it's own statistics objects in |Open|.
   void RecordStatisticsTo(MediaChannelStatistics *aStatistics) override {
diff --git a/dom/media/MediaResourceCallback.h b/dom/media/MediaResourceCallback.h
new file mode 100644
index 00000000000..1ceb1059af2
--- /dev/null
+++ b/dom/media/MediaResourceCallback.h
@@ -0,0 +1,75 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MediaResourceCallback_h_
+#define MediaResourceCallback_h_
+
+#include "nsError.h"
+
+namespace mozilla {
+
+class MediaResource;
+
+/**
+ * A callback used by MediaResource (sub-classes like FileMediaResource,
+ * RtspMediaResource, and ChannelMediaResource) to notify various events.
+ * Currently this is implemented by MediaDecoder only.
+ *
+ * Since this class has no pure virtual function, it is convenient to write
+ * gtests for the readers without using a mock MediaResource when you don't
+ * care about the events notified by the MediaResource.
+ */
+class MediaResourceCallback {
+public:
+  // Returns a weak reference to the media decoder owner.
+  virtual MediaDecoderOwner* GetMediaOwner() const { return nullptr; }
+
+  // Notify is duration is known to this MediaResource.
+  virtual void SetInfinite(bool aInfinite) {}
+
+  // Notify if seeking is supported by this MediaResource.
+  virtual void SetMediaSeekable(bool aMediaSeekable) {}
+
+  // Notify that server connection is closed.
+  virtual void ResetConnectionState() {}
+
+  // Used by RtspMediaResource which has an unusual sequence
+  // to setup the decoder.
+  virtual nsresult FinishDecoderSetup(MediaResource* aResource) {
+    return NS_OK;
+  }
+
+  // Notify that a network error is encountered.
+  virtual void NotifyNetworkError() {}
+
+  // Notify that decoding has failed.
+  virtual void NotifyDecodeError() {}
+
+  // Notify that data arrives on the stream and is read into the cache.
+  virtual void NotifyDataArrived(
+    uint32_t aLength, int64_t aOffset, bool aThrottleUpdates) {}
+
+  // Notify that MediaResource has received some data.
+  virtual void NotifyBytesDownloaded() {}
+
+  // Notify download is ended.
+  // NOTE: this can be called with the media cache lock held, so don't
+  // block or do anything which might try to acquire a lock!
+  virtual void NotifyDataEnded(nsresult aStatus) {}
+
+  // Notify that the principal of MediaResource has changed.
+  virtual void NotifyPrincipalChanged() {}
+
+  // Notify that the "cache suspended" status of MediaResource changes.
+  virtual void NotifySuspendedStatusChanged() {}
+
+  // Notify the number of bytes read from the resource.
+  virtual void NotifyBytesConsumed(int64_t aBytes, int64_t aOffset) {}
+};
+
+} // namespace mozilla
+
+#endif //MediaResourceCallback_h_
diff --git a/dom/media/RtspMediaResource.cpp b/dom/media/RtspMediaResource.cpp
index 394c28cb47e..bd864da809b 100644
--- a/dom/media/RtspMediaResource.cpp
+++ b/dom/media/RtspMediaResource.cpp
@@ -488,9 +488,9 @@ RtspTrackBuffer::PlayoutDelayTimerCallback(nsITimer *aTimer,
 //-----------------------------------------------------------------------------
 // RtspMediaResource
 //-----------------------------------------------------------------------------
-RtspMediaResource::RtspMediaResource(MediaDecoder* aDecoder,
+RtspMediaResource::RtspMediaResource(MediaResourceCallback* aCallback,
     nsIChannel* aChannel, nsIURI* aURI, const nsACString& aContentType)
-  : BaseMediaResource(aDecoder, aChannel, aURI, aContentType)
+  : BaseMediaResource(aCallback, aChannel, aURI, aContentType)
   , mIsConnected(false)
   , mIsLiveStream(false)
   , mHasTimestamp(true)
@@ -537,8 +537,8 @@ void RtspMediaResource::NotifySuspend(bool aIsSuspend)
   RTSPMLOG("NotifySuspend %d",aIsSuspend);
 
   mIsSuspend = aIsSuspend;
-  if (mDecoder) {
-    mDecoder->NotifySuspendedStatusChanged();
+  if (mCallback) {
+    mCallback->NotifySuspendedStatusChanged();
   }
 }
 
@@ -688,9 +688,7 @@ RtspMediaResource::OnConnected(uint8_t aTrackIdx,
   // video, we give up moving forward.
   if (!IsVideoEnabled() && IsVideo(tracks, meta)) {
     // Give up, report error to media element.
-    nsCOMPtr<nsIRunnable> event =
-      NS_NewRunnableMethod(mDecoder, &MediaDecoder::DecodeError);
-    NS_DispatchToMainThread(event);
+    mCallback->NotifyDecodeError();
     return NS_ERROR_FAILURE;
   }
   uint64_t durationUs = 0;
@@ -717,7 +715,7 @@ RtspMediaResource::OnConnected(uint8_t aTrackIdx,
     mTrackBuffer[i]->Start();
   }
 
-  if (!mDecoder) {
+  if (!mCallback) {
     return NS_ERROR_FAILURE;
   }
 
@@ -725,34 +723,30 @@ RtspMediaResource::OnConnected(uint8_t aTrackIdx,
   if (durationUs) {
     // Not live stream.
     mIsLiveStream = false;
-    mDecoder->SetInfinite(false);
+    mCallback->SetInfinite(false);
   } else {
     // Live stream.
     // Check the preference "media.realtime_decoder.enabled".
     if (!Preferences::GetBool("media.realtime_decoder.enabled", false)) {
       // Give up, report error to media element.
-      nsCOMPtr<nsIRunnable> event =
-        NS_NewRunnableMethod(mDecoder, &MediaDecoder::DecodeError);
-      NS_DispatchToMainThread(event);
+      mCallback->NotifyDecodeError();
       return NS_ERROR_FAILURE;
     } else {
       mIsLiveStream = true;
       bool seekable = false;
-      mDecoder->SetInfinite(true);
-      mDecoder->SetMediaSeekable(seekable);
+      mCallback->SetInfinite(true);
+      mCallback->SetMediaSeekable(seekable);
     }
   }
-  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
+  MediaDecoderOwner* owner = mCallback->GetMediaOwner();
   NS_ENSURE_TRUE(owner, NS_ERROR_FAILURE);
   // Fires an initial progress event.
   owner->DownloadProgressed();
 
-  dom::HTMLMediaElement* element = owner->GetMediaElement();
-  NS_ENSURE_TRUE(element, NS_ERROR_FAILURE);
+  nsresult rv = mCallback->FinishDecoderSetup(this);
+  NS_ENSURE_SUCCESS(rv, rv);
 
-  element->FinishDecoderSetup(mDecoder, this);
   mIsConnected = true;
-
   return NS_OK;
 }
 
@@ -766,7 +760,7 @@ RtspMediaResource::OnDisconnected(uint8_t aTrackIdx, nsresult aReason)
     mTrackBuffer[i]->Reset();
   }
 
-  if (mDecoder) {
+  if (mCallback) {
     if (aReason == NS_ERROR_NOT_INITIALIZED ||
         aReason == NS_ERROR_CONNECTION_REFUSED ||
         aReason == NS_ERROR_NOT_CONNECTED ||
@@ -774,11 +768,11 @@ RtspMediaResource::OnDisconnected(uint8_t aTrackIdx, nsresult aReason)
       // Report error code to Decoder.
       RTSPMLOG("Error in OnDisconnected 0x%x", aReason);
       mIsConnected = false;
-      mDecoder->NetworkError();
+      mCallback->NotifyNetworkError();
     } else {
       // Resetting the decoder and media element when the connection
       // between RTSP client and server goes down.
-      mDecoder->ResetConnectionState();
+      mCallback->ResetConnectionState();
     }
   }
 
@@ -796,18 +790,18 @@ void RtspMediaResource::Suspend(bool aCloseImmediately)
   NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");
 
   mIsSuspend = true;
-  if (NS_WARN_IF(!mDecoder)) {
+  if (NS_WARN_IF(!mCallback)) {
     return;
   }
 
-  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
+  MediaDecoderOwner* owner = mCallback->GetMediaOwner();
   NS_ENSURE_TRUE_VOID(owner);
   dom::HTMLMediaElement* element = owner->GetMediaElement();
   NS_ENSURE_TRUE_VOID(element);
 
   mMediaStreamController->Suspend();
   element->DownloadSuspended();
-  mDecoder->NotifySuspendedStatusChanged();
+  mCallback->NotifySuspendedStatusChanged();
 }
 
 void RtspMediaResource::Resume()
@@ -815,11 +809,11 @@ void RtspMediaResource::Resume()
   NS_ASSERTION(NS_IsMainThread(), "Don't call on non-main thread");
 
   mIsSuspend = false;
-  if (NS_WARN_IF(!mDecoder)) {
+  if (NS_WARN_IF(!mCallback)) {
     return;
   }
 
-  MediaDecoderOwner* owner = mDecoder->GetMediaOwner();
+  MediaDecoderOwner* owner = mCallback->GetMediaOwner();
   NS_ENSURE_TRUE_VOID(owner);
   dom::HTMLMediaElement* element = owner->GetMediaElement();
   NS_ENSURE_TRUE_VOID(element);
@@ -828,7 +822,7 @@ void RtspMediaResource::Resume()
     element->DownloadResumed();
   }
   mMediaStreamController->Resume();
-  mDecoder->NotifySuspendedStatusChanged();
+  mCallback->NotifySuspendedStatusChanged();
 }
 
 nsresult RtspMediaResource::Open(nsIStreamListener **aStreamListener)
@@ -840,11 +834,11 @@ nsresult RtspMediaResource::Close()
 {
   NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
   mMediaStreamController->Stop();
-  // Since mDecoder is not an nsCOMPtr in BaseMediaResource, we have to
+  // Since mCallback is not an nsCOMPtr in BaseMediaResource, we have to
   // explicitly set it as null pointer in order to prevent misuse from this
   // object (RtspMediaResource).
-  if (mDecoder) {
-    mDecoder = nullptr;
+  if (mCallback) {
+    mCallback = nullptr;
   }
   return NS_OK;
 }
@@ -866,7 +860,7 @@ nsresult RtspMediaResource::SeekTime(int64_t aOffset)
   NS_ASSERTION(!NS_IsMainThread(), "Don't call on main thread");
 
   RTSPMLOG("Seek requested for aOffset [%lld] for decoder [%p]",
-           aOffset, mDecoder);
+           aOffset, mCallback);
   // Clear buffer and raise the frametype flag.
   for(uint32_t i = 0 ; i < mTrackBuffer.Length(); ++i) {
     mTrackBuffer[i]->ResetWithFrameType(MEDIASTREAM_FRAMETYPE_DISCONTINUITY);
diff --git a/dom/media/RtspMediaResource.h b/dom/media/RtspMediaResource.h
index 3943d9b692d..224da67b5ec 100644
--- a/dom/media/RtspMediaResource.h
+++ b/dom/media/RtspMediaResource.h
@@ -71,7 +71,7 @@ class RtspTrackBuffer;
 class RtspMediaResource : public BaseMediaResource
 {
 public:
-  RtspMediaResource(MediaDecoder* aDecoder, nsIChannel* aChannel, nsIURI* aURI,
+  RtspMediaResource(MediaResourceCallback* aCallback, nsIChannel* aChannel, nsIURI* aURI,
                     const nsACString& aContentType);
   virtual ~RtspMediaResource();
 
@@ -176,7 +176,7 @@ public:
   virtual bool     CanClone() override {
     return false;
   }
-  virtual already_AddRefed<MediaResource> CloneData(MediaDecoder* aDecoder)
+  virtual already_AddRefed<MediaResource> CloneData(MediaResourceCallback*)
   override {
     return nullptr;
   }
diff --git a/dom/media/eme/MediaKeySystemAccess.cpp b/dom/media/eme/MediaKeySystemAccess.cpp
index d10d2c83c4f..8c807a93cbd 100644
--- a/dom/media/eme/MediaKeySystemAccess.cpp
+++ b/dom/media/eme/MediaKeySystemAccess.cpp
@@ -52,10 +52,12 @@ NS_INTERFACE_MAP_END
 
 MediaKeySystemAccess::MediaKeySystemAccess(nsPIDOMWindow* aParent,
                                            const nsAString& aKeySystem,
-                                           const nsAString& aCDMVersion)
+                                           const nsAString& aCDMVersion,
+                                           const MediaKeySystemConfiguration& aConfig)
   : mParent(aParent)
   , mKeySystem(aKeySystem)
   , mCDMVersion(aCDMVersion)
+  , mConfig(aConfig)
 {
 }
 
@@ -81,6 +83,12 @@ MediaKeySystemAccess::GetKeySystem(nsString& aOutKeySystem) const
   ConstructKeySystem(mKeySystem, mCDMVersion, aOutKeySystem);
 }
 
+void
+MediaKeySystemAccess::GetConfiguration(MediaKeySystemConfiguration& aConfig)
+{
+  aConfig = mConfig;
+}
+
 already_AddRefed<Promise>
 MediaKeySystemAccess::CreateMediaKeys(ErrorResult& aRv)
 {
@@ -373,39 +381,114 @@ GMPDecryptsAndGeckoDecodesAAC(mozIGeckoMediaPluginService* aGMPService,
     ) && MP4Decoder::CanHandleMediaType(aContentType);
 }
 
+static bool
+IsSupportedAudio(mozIGeckoMediaPluginService* aGMPService,
+                 const nsAString& aKeySystem,
+                 const nsAString& aAudioType)
+{
+  return IsAACContentType(aAudioType) &&
+         (GMPDecryptsAndDecodesAAC(aGMPService, aKeySystem) ||
+          GMPDecryptsAndGeckoDecodesAAC(aGMPService, aKeySystem, aAudioType));
+}
+
+static bool
+IsSupportedVideo(mozIGeckoMediaPluginService* aGMPService,
+                 const nsAString& aKeySystem,
+                 const nsAString& aVideoType)
+{
+  return IsH264ContentType(aVideoType) &&
+         (GMPDecryptsAndDecodesH264(aGMPService, aKeySystem) ||
+          GMPDecryptsAndGeckoDecodesH264(aGMPService, aKeySystem, aVideoType));
+}
+
 static bool
 IsSupported(mozIGeckoMediaPluginService* aGMPService,
             const nsAString& aKeySystem,
-            const MediaKeySystemOptions& aConfig)
+            const MediaKeySystemConfiguration& aConfig)
 {
-  if (!aConfig.mInitDataType.EqualsLiteral("cenc")) {
+  if (aConfig.mInitDataType.IsEmpty() &&
+      aConfig.mAudioType.IsEmpty() &&
+      aConfig.mVideoType.IsEmpty()) {
+    // Not an old-style request.
     return false;
   }
-  if (!aConfig.mAudioCapability.IsEmpty() ||
-      !aConfig.mVideoCapability.IsEmpty()) {
-    // Don't support any capabilities until we know we have a CDM with
-    // capabilities...
+
+  // Backwards compatibility with legacy MediaKeySystemConfiguration method.
+  if (!aConfig.mInitDataType.IsEmpty() &&
+      !aConfig.mInitDataType.EqualsLiteral("cenc")) {
     return false;
   }
   if (!aConfig.mAudioType.IsEmpty() &&
-      (!IsAACContentType(aConfig.mAudioType) ||
-       (!GMPDecryptsAndDecodesAAC(aGMPService, aKeySystem) &&
-        !GMPDecryptsAndGeckoDecodesAAC(aGMPService, aKeySystem, aConfig.mAudioType)))) {
+      !IsSupportedAudio(aGMPService, aKeySystem, aConfig.mAudioType)) {
     return false;
   }
   if (!aConfig.mVideoType.IsEmpty() &&
-      (!IsH264ContentType(aConfig.mVideoType) ||
-       (!GMPDecryptsAndDecodesH264(aGMPService, aKeySystem) &&
-        !GMPDecryptsAndGeckoDecodesH264(aGMPService, aKeySystem, aConfig.mVideoType)))) {
+      !IsSupportedVideo(aGMPService, aKeySystem, aConfig.mVideoType)) {
     return false;
   }
+
   return true;
 }
 
+static bool
+GetSupportedConfig(mozIGeckoMediaPluginService* aGMPService,
+                   const nsAString& aKeySystem,
+                   const MediaKeySystemConfiguration& aCandidate,
+                   MediaKeySystemConfiguration& aOutConfig)
+{
+  MediaKeySystemConfiguration config;
+  config.mLabel = aCandidate.mLabel;
+  if (aCandidate.mInitDataTypes.WasPassed()) {
+    nsTArray<nsString> initDataTypes;
+    for (const nsString& candidate : aCandidate.mInitDataTypes.Value()) {
+      if (candidate.EqualsLiteral("cenc")) {
+        initDataTypes.AppendElement(candidate);
+      }
+    }
+    if (initDataTypes.IsEmpty()) {
+      return false;
+    }
+    config.mInitDataTypes.Construct();
+    config.mInitDataTypes.Value().Assign(initDataTypes);
+  }
+  if (aCandidate.mAudioCapabilities.WasPassed()) {
+    nsTArray<MediaKeySystemMediaCapability> caps;
+    for (const MediaKeySystemMediaCapability& cap : aCandidate.mAudioCapabilities.Value()) {
+      if (IsSupportedAudio(aGMPService, aKeySystem, cap.mContentType)) {
+        caps.AppendElement(cap);
+      }
+    }
+    if (caps.IsEmpty()) {
+      return false;
+    }
+    config.mAudioCapabilities.Construct();
+    config.mAudioCapabilities.Value().Assign(caps);
+  }
+  if (aCandidate.mVideoCapabilities.WasPassed()) {
+    nsTArray<MediaKeySystemMediaCapability> caps;
+    for (const MediaKeySystemMediaCapability& cap : aCandidate.mVideoCapabilities.Value()) {
+      if (IsSupportedVideo(aGMPService, aKeySystem, cap.mContentType)) {
+        caps.AppendElement(cap);
+      }
+    }
+    if (caps.IsEmpty()) {
+      return false;
+    }
+    config.mVideoCapabilities.Construct();
+    config.mVideoCapabilities.Value().Assign(caps);
+  }
+
+  aOutConfig = config;
+
+  return true;
+}
+
+// Backwards compatibility with legacy requestMediaKeySystemAccess with fields
+// from old MediaKeySystemOptions dictionary.
 /* static */
 bool
 MediaKeySystemAccess::IsSupported(const nsAString& aKeySystem,
-                                  const Sequence<MediaKeySystemOptions>& aOptions)
+                                  const Sequence<MediaKeySystemConfiguration>& aConfigs)
 {
   nsCOMPtr<mozIGeckoMediaPluginService> mps =
     do_GetService("@mozilla.org/gecko-media-plugin-service;1");
@@ -419,7 +502,7 @@ MediaKeySystemAccess::IsSupported(const nsAString& aKeySystem,
     return false;
   }
 
-  for (const MediaKeySystemOptions& config : aOptions) {
+  for (const MediaKeySystemConfiguration& config : aConfigs) {
     if (mozilla::dom::IsSupported(mps, aKeySystem, config)) {
       return true;
     }
@@ -427,6 +510,34 @@ MediaKeySystemAccess::IsSupported(const nsAString& aKeySystem,
   return false;
 }
 
+/* static */
+bool
+MediaKeySystemAccess::GetSupportedConfig(const nsAString& aKeySystem,
+                                         const Sequence<MediaKeySystemConfiguration>& aConfigs,
+                                         MediaKeySystemConfiguration& aOutConfig)
+{
+  nsCOMPtr<mozIGeckoMediaPluginService> mps =
+    do_GetService("@mozilla.org/gecko-media-plugin-service;1");
+  if (NS_WARN_IF(!mps)) {
+    return false;
+  }
+
+  if (!HaveGMPFor(mps,
+                  NS_ConvertUTF16toUTF8(aKeySystem),
+                  NS_LITERAL_CSTRING(GMP_API_DECRYPTOR))) {
+    return false;
+  }
+
+  for (const MediaKeySystemConfiguration& config : aConfigs) {
+    if (mozilla::dom::GetSupportedConfig(mps, aKeySystem, config, aOutConfig)) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+
 /* static */
 void
 MediaKeySystemAccess::NotifyObservers(nsIDOMWindow* aWindow,
diff --git a/dom/media/eme/MediaKeySystemAccess.h b/dom/media/eme/MediaKeySystemAccess.h
index 6123bd10f46..e6198ad9f88 100644
--- a/dom/media/eme/MediaKeySystemAccess.h
+++ b/dom/media/eme/MediaKeySystemAccess.h
@@ -31,7 +31,8 @@ public:
 public:
   explicit MediaKeySystemAccess(nsPIDOMWindow* aParent,
                                 const nsAString& aKeySystem,
-                                const nsAString& aCDMVersion);
+                                const nsAString& aCDMVersion,
+                                const MediaKeySystemConfiguration& aConfig);
 
 protected:
   ~MediaKeySystemAccess();
@@ -43,6 +44,8 @@ public:
 
   void GetKeySystem(nsString& aRetVal) const;
 
+  void GetConfiguration(MediaKeySystemConfiguration& aConfig);
+
   already_AddRefed<Promise> CreateMediaKeys(ErrorResult& aRv);
 
 
@@ -53,7 +56,7 @@ public:
                                                  nsACString& aOutCdmVersion);
 
   static bool IsSupported(const nsAString& aKeySystem,
-                          const Sequence<MediaKeySystemOptions>& aOptions);
+                          const Sequence<MediaKeySystemConfiguration>& aConfigs);
 
   static void NotifyObservers(nsIDOMWindow* aWindow,
                               const nsAString& aKeySystem,
@@ -63,10 +66,15 @@ public:
                                  const nsACString& aVersion,
                                  nsACString& aOutMessage);
 
+  static bool GetSupportedConfig(const nsAString& aKeySystem,
+                                 const Sequence<MediaKeySystemConfiguration>& aConfigs,
+                                 MediaKeySystemConfiguration& aOutConfig);
+
 private:
   nsCOMPtr<nsPIDOMWindow> mParent;
   const nsString mKeySystem;
   const nsString mCDMVersion;
+  const MediaKeySystemConfiguration mConfig;
 };
 
 } // namespace dom
diff --git a/dom/media/eme/MediaKeySystemAccessManager.cpp b/dom/media/eme/MediaKeySystemAccessManager.cpp
index 1f02d98bc8e..e0df40b00f4 100644
--- a/dom/media/eme/MediaKeySystemAccessManager.cpp
+++ b/dom/media/eme/MediaKeySystemAccessManager.cpp
@@ -63,16 +63,14 @@ MediaKeySystemAccessManager::~MediaKeySystemAccessManager()
 void
 MediaKeySystemAccessManager::Request(DetailedPromise* aPromise,
                                      const nsAString& aKeySystem,
-                                     const Optional<Sequence<MediaKeySystemOptions>>& aOptions)
+                                     const Sequence<MediaKeySystemConfiguration>& aConfigs)
 {
-  if (aKeySystem.IsEmpty() || (aOptions.WasPassed() && aOptions.Value().IsEmpty())) {
+  if (aKeySystem.IsEmpty() || aConfigs.IsEmpty()) {
     aPromise->MaybeReject(NS_ERROR_DOM_INVALID_ACCESS_ERR,
                           NS_LITERAL_CSTRING("Invalid keysystem type or invalid options sequence"));
     return;
   }
-  Sequence<MediaKeySystemOptions> optionsNotPassed;
-  const auto& options = aOptions.WasPassed() ? aOptions.Value() : optionsNotPassed;
-  Request(aPromise, aKeySystem, options, RequestType::Initial);
+  Request(aPromise, aKeySystem, aConfigs, RequestType::Initial);
 }
 
 static bool
@@ -91,7 +89,7 @@ ShouldTrialCreateGMP(const nsAString& aKeySystem)
 void
 MediaKeySystemAccessManager::Request(DetailedPromise* aPromise,
                                      const nsAString& aKeySystem,
-                                     const Sequence<MediaKeySystemOptions>& aOptions,
+                                     const Sequence<MediaKeySystemConfiguration>& aConfigs,
                                      RequestType aType)
 {
   EME_LOG("MediaKeySystemAccessManager::Request %s", NS_ConvertUTF16toUTF8(aKeySystem).get());
@@ -145,7 +143,7 @@ MediaKeySystemAccessManager::Request(DetailedPromise* aPromise,
     // has had a new plugin added. AwaitInstall() sets a timer to fail if the
     // update/download takes too long or fails.
     if (aType == RequestType::Initial &&
-        AwaitInstall(aPromise, aKeySystem, aOptions)) {
+        AwaitInstall(aPromise, aKeySystem, aConfigs)) {
       // Notify chrome that we're going to wait for the CDM to download/update.
       // Note: If we're re-trying, we don't re-send the notificaiton,
       // as chrome is already displaying the "we can't play, updating"
@@ -174,10 +172,13 @@ MediaKeySystemAccessManager::Request(DetailedPromise* aPromise,
     return;
   }
 
-  if (aOptions.IsEmpty() ||
-      MediaKeySystemAccess::IsSupported(keySystem, aOptions)) {
+  MediaKeySystemConfiguration config;
+  // TODO: Remove IsSupported() check here once we remove backwards
+  // compatibility with initial implementation...
+  if (MediaKeySystemAccess::GetSupportedConfig(keySystem, aConfigs, config) ||
+      MediaKeySystemAccess::IsSupported(keySystem, aConfigs)) {
     RefPtr<MediaKeySystemAccess> access(
-      new MediaKeySystemAccess(mWindow, keySystem, NS_ConvertUTF8toUTF16(cdmVersion)));
+      new MediaKeySystemAccess(mWindow, keySystem, NS_ConvertUTF8toUTF16(cdmVersion), config));
    if (ShouldTrialCreateGMP(keySystem)) {
       // Ensure we have tried creating a GMPVideoDecoder for this
       // keySystem, and that we can use it to decode. This ensures that we only
@@ -195,11 +196,11 @@ MediaKeySystemAccessManager::Request(DetailedPromise* aPromise,
 
 MediaKeySystemAccessManager::PendingRequest::PendingRequest(DetailedPromise* aPromise,
                                                             const nsAString& aKeySystem,
-                                                            const Sequence<MediaKeySystemOptions>& aOptions,
+                                                            const Sequence<MediaKeySystemConfiguration>& aConfigs,
                                                             nsITimer* aTimer)
   : mPromise(aPromise)
   , mKeySystem(aKeySystem)
-  , mOptions(aOptions)
+  , mConfigs(aConfigs)
   , mTimer(aTimer)
 {
   MOZ_COUNT_CTOR(MediaKeySystemAccessManager::PendingRequest);
@@ -208,7 +209,7 @@ MediaKeySystemAccessManager::PendingRequest::PendingRequest(DetailedPromise* aPr
 MediaKeySystemAccessManager::PendingRequest::PendingRequest(const PendingRequest& aOther)
   : mPromise(aOther.mPromise)
   , mKeySystem(aOther.mKeySystem)
-  , mOptions(aOther.mOptions)
+  , mConfigs(aOther.mConfigs)
   , mTimer(aOther.mTimer)
 {
   MOZ_COUNT_CTOR(MediaKeySystemAccessManager::PendingRequest);
@@ -238,7 +239,7 @@ MediaKeySystemAccessManager::PendingRequest::RejectPromise(const nsCString& aRea
 bool
 MediaKeySystemAccessManager::AwaitInstall(DetailedPromise* aPromise,
                                           const nsAString& aKeySystem,
-                                          const Sequence<MediaKeySystemOptions>& aOptions)
+                                          const Sequence<MediaKeySystemConfiguration>& aConfigs)
 {
   EME_LOG("MediaKeySystemAccessManager::AwaitInstall %s", NS_ConvertUTF16toUTF8(aKeySystem).get());
 
@@ -253,7 +254,7 @@ MediaKeySystemAccessManager::AwaitInstall(DetailedPromise* aPromise,
     return false;
   }
 
-  mRequests.AppendElement(PendingRequest(aPromise, aKeySystem, aOptions, timer));
+  mRequests.AppendElement(PendingRequest(aPromise, aKeySystem, aConfigs, timer));
   return true;
 }
 
@@ -261,7 +262,7 @@ void
 MediaKeySystemAccessManager::RetryRequest(PendingRequest& aRequest)
 {
   aRequest.CancelTimer();
-  Request(aRequest.mPromise, aRequest.mKeySystem, aRequest.mOptions, RequestType::Subsequent);
+  Request(aRequest.mPromise, aRequest.mKeySystem, aRequest.mConfigs, RequestType::Subsequent);
 }
 
 nsresult
diff --git a/dom/media/eme/MediaKeySystemAccessManager.h b/dom/media/eme/MediaKeySystemAccessManager.h
index 6f2cc4d3e98..05060ba097c 100644
--- a/dom/media/eme/MediaKeySystemAccessManager.h
+++ b/dom/media/eme/MediaKeySystemAccessManager.h
@@ -30,14 +30,14 @@ public:
 
   void Request(DetailedPromise* aPromise,
                const nsAString& aKeySystem,
-               const Optional<Sequence<MediaKeySystemOptions>>& aOptions);
+               const Sequence<MediaKeySystemConfiguration>& aConfig);
 
   void Shutdown();
 
   struct PendingRequest {
     PendingRequest(DetailedPromise* aPromise,
                    const nsAString& aKeySystem,
-                   const Sequence<MediaKeySystemOptions>& aOptions,
+                   const Sequence<MediaKeySystemConfiguration>& aConfig,
                    nsITimer* aTimer);
     PendingRequest(const PendingRequest& aOther);
     ~PendingRequest();
@@ -46,7 +46,7 @@ public:
 
     RefPtr<DetailedPromise> mPromise;
     const nsString mKeySystem;
-    const Sequence<MediaKeySystemOptions> mOptions;
+    const Sequence<MediaKeySystemConfiguration> mConfigs;
     nsCOMPtr<nsITimer> mTimer;
   };
 
@@ -59,7 +59,7 @@ private:
 
   void Request(DetailedPromise* aPromise,
                const nsAString& aKeySystem,
-               const Sequence<MediaKeySystemOptions>& aOptions,
+               const Sequence<MediaKeySystemConfiguration>& aConfig,
                RequestType aType);
 
   ~MediaKeySystemAccessManager();
@@ -68,7 +68,7 @@ private:
 
   bool AwaitInstall(DetailedPromise* aPromise,
                     const nsAString& aKeySystem,
-                    const Sequence<MediaKeySystemOptions>& aOptions);
+                    const Sequence<MediaKeySystemConfiguration>& aConfig);
 
   void RetryRequest(PendingRequest& aRequest);
 
diff --git a/dom/media/eme/MediaKeys.cpp b/dom/media/eme/MediaKeys.cpp
index 30f4496a32c..6663dfcb3a9 100644
--- a/dom/media/eme/MediaKeys.cpp
+++ b/dom/media/eme/MediaKeys.cpp
@@ -312,9 +312,8 @@ MediaKeys::Init(ErrorResult& aRv)
                          NS_LITERAL_CSTRING("Couldn't get top-level window in MediaKeys::Init"));
     return promise.forget();
   }
-  nsCOMPtr<nsIDOMWindow> topWindow;
-  window->GetTop(getter_AddRefs(topWindow));
-  nsCOMPtr<nsPIDOMWindow> top = do_QueryInterface(topWindow);
+  window = window->GetOuterWindow();
+  nsCOMPtr<nsPIDOMWindow> top = window->GetTop();
   if (!top || !top->GetExtantDoc()) {
     promise->MaybeReject(NS_ERROR_DOM_INVALID_STATE_ERR,
                          NS_LITERAL_CSTRING("Couldn't get document in MediaKeys::Init"));
diff --git a/dom/media/gtest/MockMediaResource.h b/dom/media/gtest/MockMediaResource.h
index 957367555f6..20a0ea4cab0 100644
--- a/dom/media/gtest/MockMediaResource.h
+++ b/dom/media/gtest/MockMediaResource.h
@@ -25,7 +25,7 @@ public:
     return nullptr;
   }
   virtual bool CanClone() override { return false; }
-  virtual already_AddRefed<MediaResource> CloneData(MediaDecoder* aDecoder)
+  virtual already_AddRefed<MediaResource> CloneData(MediaResourceCallback*)
     override
   {
     return nullptr;
diff --git a/dom/media/mediasource/MediaSourceResource.h b/dom/media/mediasource/MediaSourceResource.h
index 1c6e019e40d..38b2c347fb2 100644
--- a/dom/media/mediasource/MediaSourceResource.h
+++ b/dom/media/mediasource/MediaSourceResource.h
@@ -32,7 +32,7 @@ public:
   virtual void Suspend(bool aCloseImmediately) override { UNIMPLEMENTED(); }
   virtual void Resume() override { UNIMPLEMENTED(); }
   virtual bool CanClone() override { UNIMPLEMENTED(); return false; }
-  virtual already_AddRefed<MediaResource> CloneData(MediaDecoder* aDecoder) override { UNIMPLEMENTED(); return nullptr; }
+  virtual already_AddRefed<MediaResource> CloneData(MediaResourceCallback*) override { UNIMPLEMENTED(); return nullptr; }
   virtual void SetReadMode(MediaCacheStream::ReadMode aMode) override { UNIMPLEMENTED(); }
   virtual void SetPlaybackRate(uint32_t aBytesPerSecond) override  { UNIMPLEMENTED(); }
   virtual nsresult ReadAt(int64_t aOffset, char* aBuffer, uint32_t aCount, uint32_t* aBytes) override { UNIMPLEMENTED(); return NS_ERROR_FAILURE; }
diff --git a/dom/media/mediasource/SourceBufferResource.h b/dom/media/mediasource/SourceBufferResource.h
index 0a47fcbdc10..bac9b4c08a2 100644
--- a/dom/media/mediasource/SourceBufferResource.h
+++ b/dom/media/mediasource/SourceBufferResource.h
@@ -43,7 +43,7 @@ public:
   virtual void Suspend(bool aCloseImmediately) override { UNIMPLEMENTED(); }
   virtual void Resume() override { UNIMPLEMENTED(); }
   virtual already_AddRefed<nsIPrincipal> GetCurrentPrincipal() override { UNIMPLEMENTED(); return nullptr; }
-  virtual already_AddRefed<MediaResource> CloneData(MediaDecoder* aDecoder) override { UNIMPLEMENTED(); return nullptr; }
+  virtual already_AddRefed<MediaResource> CloneData(MediaResourceCallback*) override { UNIMPLEMENTED(); return nullptr; }
   virtual void SetReadMode(MediaCacheStream::ReadMode aMode) override { UNIMPLEMENTED(); }
   virtual void SetPlaybackRate(uint32_t aBytesPerSecond) override { UNIMPLEMENTED(); }
   virtual nsresult ReadAt(int64_t aOffset, char* aBuffer, uint32_t aCount, uint32_t* aBytes) override;
diff --git a/dom/media/moz.build b/dom/media/moz.build
index bdacd29ad4b..3274afa86a0 100644
--- a/dom/media/moz.build
+++ b/dom/media/moz.build
@@ -129,6 +129,7 @@ EXPORTS += [
     'MediaQueue.h',
     'MediaRecorder.h',
     'MediaResource.h',
+    'MediaResourceCallback.h',
     'MediaSegment.h',
     'MediaStatistics.h',
     'MediaStreamGraph.h',
diff --git a/dom/media/test/eme.js b/dom/media/test/eme.js
index e7c4abad177..86593dc547b 100644
--- a/dom/media/test/eme.js
+++ b/dom/media/test/eme.js
@@ -369,14 +369,15 @@ function SetupEME(test, token, params)
         })
       }
 
-      var options = [
-         {
-           initDataType: ev.initDataType,
-           videoType: streamType("video"),
-           audioType: streamType("audio"),
-         }
-       ];
-      var p = navigator.requestMediaKeySystemAccess(KEYSYSTEM_TYPE, options);
+      var options = { initDataTypes: [ev.initDataType] };
+      if (streamType("video")) {
+        options.videoCapabilities = [{contentType: streamType("video")}];
+      }
+      if (streamType("audio")) {
+        options.audioCapabilities = [{contentType: streamType("audio")}];
+      }
+
+      var p = navigator.requestMediaKeySystemAccess(KEYSYSTEM_TYPE, [options]);
       var r = bail(token + " Failed to request key system access.");
       chain(p, r)
       .then(function(keySystemAccess) {
diff --git a/dom/media/test/test_eme_non_mse_fails.html b/dom/media/test/test_eme_non_mse_fails.html
index 64e05a1b054..d8fa48e4922 100644
--- a/dom/media/test/test_eme_non_mse_fails.html
+++ b/dom/media/test/test_eme_non_mse_fails.html
@@ -15,9 +15,9 @@ var manager = new MediaTestManager;
 function DoSetMediaKeys(v, test)
 {
   var options = [{
-    initDataType: "cenc",
-    audioType: test.audioType,
-    videoType: test.videoType,
+    initDataTypes: ["cenc"],
+    audioCapabilities: [{contentType: test.audioType}],
+    videoCapabilities: [{contentType: test.videoType}],
   }];
 
   return navigator.requestMediaKeySystemAccess("org.w3.clearkey", options)
diff --git a/dom/media/test/test_eme_persistent_sessions.html b/dom/media/test/test_eme_persistent_sessions.html
index 1e323e78a30..b1a808a0abe 100644
--- a/dom/media/test/test_eme_persistent_sessions.html
+++ b/dom/media/test/test_eme_persistent_sessions.html
@@ -86,7 +86,7 @@ function startTest(test, token)
 
         // Once the session is closed, reload the MediaKeys and reload the session
         .then(function() {
-          return navigator.requestMediaKeySystemAccess(KEYSYSTEM_TYPE);
+          return navigator.requestMediaKeySystemAccess(KEYSYSTEM_TYPE, [{initDataTypes:["cenc"]}]);
         })
 
         .then(function(requestedKeySystemAccess) {
diff --git a/dom/media/test/test_eme_requestKeySystemAccess.html b/dom/media/test/test_eme_requestKeySystemAccess.html
index e2402c7ce70..d9261c02232 100644
--- a/dom/media/test/test_eme_requestKeySystemAccess.html
+++ b/dom/media/test/test_eme_requestKeySystemAccess.html
@@ -13,6 +13,31 @@
 
 const CLEARKEY_ID = 'org.w3.clearkey';
 const CLEARKEY_VERSION = '1';
+const SUPPORTED_LABEL = "pass label";
+
+function ValidateConfig(name, expected, observed) {
+  info("ValidateConfig " + name);
+  info("expected cfg=" + JSON.stringify(expected));
+  info("observed cfg=" + JSON.stringify(observed));
+
+  is(observed.label, expected.label, name + " label should match");
+  if (expected.initDataTypes) {
+    ok(expected.initDataTypes.every((element, index, array) => observed.initDataTypes.includes(element)), name + " initDataTypes should match.");
+  }
+
+  if (expected.audioCapabilities) {
+    ok(expected.audioCapabilities.length == 1, "Test function can only handle one capability.");
+    ok(observed.audioCapabilities.length == 1, "Test function can only handle one capability.");
+    is(observed.audioCapabilities[0].contentType, expected.audioCapabilities[0].contentType, name + " audioCapabilities should match.");
+  }
+  if (typeof expected.videoCapabilities !== 'undefined') {
+    info("expected.videoCapabilities=" + expected.videoCapabilities);
+    dump("expected.videoCapabilities=" + expected.videoCapabilities + "\n");
+    ok(expected.videoCapabilities.length == 1, "Test function can only handle one capability.");
+    ok(observed.videoCapabilities.length == 1, "Test function can only handle one capability.");
+    is(observed.videoCapabilities[0].contentType, expected.videoCapabilities[0].contentType, name + " videoCapabilities should match.");
+  }
+}
 
 function Test(test) {
   var name = "'" + test.name + "'";
@@ -27,6 +52,7 @@ function Test(test) {
       function(keySystemAccess) {
         ok(test.shouldPass, name + " passed and was expected to " + (test.shouldPass ? "pass" : "fail"));
         is(keySystemAccess.keySystem, CLEARKEY_ID + "." + CLEARKEY_VERSION, "CDM version should be in MediaKeySystemAccess.keySystem");
+        ValidateConfig(name, test.expectedConfig, keySystemAccess.getConfiguration());
         resolve();
       },
       function(ex) {
@@ -43,7 +69,12 @@ var tests = [
   {
     name: 'Empty keySystem string',
     keySystem: '',
-    options: [ ],
+    options: [
+      {
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4'}],
+      }
+    ],
     shouldPass: false,
   },
   {
@@ -55,23 +86,34 @@ var tests = [
   {
     name: 'Undefined options',
     keySystem: CLEARKEY_ID,
-    shouldPass: true,
+    shouldPass: false,
   },
   {
     name: 'Basic MP4 cenc',
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        videoType: 'video/mp4',
+        label: SUPPORTED_LABEL,
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4'}],
       }
     ],
+    expectedConfig: {
+      label: SUPPORTED_LABEL,
+      initDataTypes: ['cenc'],
+      videoCapabilities: [{contentType: 'video/mp4'}],
+    },
     shouldPass: true,
   },
   {
     name: 'Invalid keysystem failure',
     keySystem: 'bogusKeySystem',
-    options: [],
+    options: [
+      {
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4'}],
+      }
+    ],
     shouldPass: false,
   },
   {
@@ -79,7 +121,32 @@ var tests = [
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'bogus',
+        initDataTypes: ['bogus'],
+      }
+    ],
+    shouldPass: false,
+  },
+  {
+    name: 'Valid initDataType after invalid',
+    keySystem: CLEARKEY_ID,
+    options: [
+      {
+        label: SUPPORTED_LABEL,
+        initDataTypes: ['bogus', 'invalid', 'cenc'],
+      }
+    ],
+    expectedConfig: {
+      label: SUPPORTED_LABEL,
+      initDataTypes: ['cenc'],
+    },
+    shouldPass: true,
+  },
+  {
+    name: 'Empty initDataTypes',
+    keySystem: CLEARKEY_ID,
+    options: [
+      {
+        initDataTypes: [],
       }
     ],
     shouldPass: false,
@@ -89,72 +156,102 @@ var tests = [
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        videoType: 'video/bogus',
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/bogus'}],
       }
     ],
     shouldPass: false,
   },
   {
-    name: 'Invalid statefulness',
+    name: 'distinctiveIdentifier, persistentState, and robustness ignored',
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        videoType: 'video/mp4',
-        stateful: 'bogus',
+        label: SUPPORTED_LABEL,
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4', robustness: 'somewhat'}],
+        distinctiveIdentifier: 'bogus',
+        persistentState: 'bogus',
+      }
+    ],
+    expectedConfig: {
+      label: SUPPORTED_LABEL,
+      initDataTypes: ['cenc'],
+      videoCapabilities: [{contentType: 'video/mp4'}],
+    },
+    shouldPass: true,
+  },
+  {
+    name: 'Only unrecognised dict entries specified with unrecognised video type',
+    keySystem: CLEARKEY_ID,
+    options: [
+      {
+        videoCapabilities: [{robustness: 'very much so'}],
+        distinctiveIdentifier: 'required',
+        persistentState: 'required',
       }
     ],
     shouldPass: false,
   },
   {
-    name: 'Invalid uniqueidentifier',
+    name: 'Only unrecognised dict entries specified should be ignored',
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        videoType: 'video/mp4',
-        uniqueidentifier: 'bogus',
+        label: SUPPORTED_LABEL,
+        distinctiveIdentifier: 'required',
+        persistentState: 'required',
       }
     ],
-    shouldPass: false,
+    expectedConfig: {
+      label: SUPPORTED_LABEL,
+    },
+    shouldPass: true,
   },
   {
-    name: 'Audio capabilities not supported by CLEARKEY_ID',
+    name: 'Empty config dict',
     keySystem: CLEARKEY_ID,
-    options: [
-      {
-        initDataType: 'cenc',
-        videoType: 'video/mp4',
-        audioCapability: 'bogus',
-      }
-    ],
-    shouldPass: false,
+    options: [{ label: SUPPORTED_LABEL }],
+    expectedConfig: {
+      label: SUPPORTED_LABEL
+    },
+    shouldPass: true,
   },
   {
-    name: 'Video capabilities not supported by CLEARKEY_ID',
+    name: 'Unexpected config entry should be ignored',
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        videoType: 'video/mp4',
-        videoCapability: 'bogus',
+        label: SUPPORTED_LABEL,
+        initDataTypes: ['cenc'],
+        unexpectedEntry: 'this should be ignored',
       }
     ],
-    shouldPass: false,
+    expectedConfig: {
+      label: SUPPORTED_LABEL,
+      initDataTypes: ['cenc'],
+    },
+    shouldPass: true,
   },
   {
     name: 'Invalid option followed by valid',
     keySystem: CLEARKEY_ID,
     options: [
       {
-        bogus: 'bogon',
+        label: "this config should not be supported",
+        initDataTypes: ['bogus'],
       },
       {
-        initDataType: 'cenc',
-        videoType: 'video/mp4',
+        label: SUPPORTED_LABEL,
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4'}],
       }
     ],
+    expectedConfig: {
+      label: SUPPORTED_LABEL,
+      initDataTypes: ['cenc'],
+      videoCapabilities: [{contentType: 'video/mp4'}],
+    },
     shouldPass: true,
   },
   {
@@ -162,10 +259,16 @@ var tests = [
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        audioType: 'audio/mp4',
+        label: SUPPORTED_LABEL,
+        initDataTypes: ['cenc'],
+        audioCapabilities: [{contentType: 'audio/mp4'}],
       }
     ],
+    expectedConfig: {
+      label: SUPPORTED_LABEL,
+      initDataTypes: ['cenc'],
+      audioCapabilities: [{contentType: 'audio/mp4'}],
+    },
     shouldPass: true,
   },
   {
@@ -173,10 +276,16 @@ var tests = [
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        audioType: 'audio/mp4; codecs="mp4a.40.2"',
+        label: SUPPORTED_LABEL,
+        initDataTypes: ['cenc'],
+        audioCapabilities: [{contentType: 'audio/mp4; codecs="mp4a.40.2"'}],
       }
     ],
+    expectedConfig: {
+      label: SUPPORTED_LABEL,
+      initDataTypes: ['cenc'],
+      audioCapabilities: [{contentType: 'audio/mp4; codecs="mp4a.40.2"'}],
+    },
     shouldPass: true,
   },
   {
@@ -184,8 +293,8 @@ var tests = [
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        audioType: 'audio/mp4; codecs="bogus"',
+        initDataTypes: ['cenc'],
+        audioCapabilities: [{contentType: 'audio/mp4; codecs="bogus"'}],
       }
     ],
     shouldPass: false,
@@ -195,19 +304,19 @@ var tests = [
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        audioType: 'audio/mp4; codecs="mp3"',
+        initDataTypes: ['cenc'],
+        audioCapabilities: [{contentType: 'audio/mp4; codecs="mp3"'}],
       }
     ],
     shouldPass: false,
   },
   {
-    name: 'MP4 video container type with an audio codec is unsupported',
+    name: 'MP4 video container type with an mp3 codec is unsupported',
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        videoType: 'video/mp4; codecs="mp3"',
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4; codecs="mp3"'}],
       }
     ],
     shouldPass: false,
@@ -217,8 +326,8 @@ var tests = [
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        audioType: 'audio/mp4; codecs="avc1.42E01E"',
+        initDataTypes: ['cenc'],
+        audioCapabilities: [{contentType: 'audio/mp4; codecs="avc1.42E01E"'}],
       }
     ],
     shouldPass: false,
@@ -228,10 +337,16 @@ var tests = [
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        videoType: 'video/mp4; codecs="avc1.42E01E"',
+        label: SUPPORTED_LABEL,
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4; codecs="avc1.42E01E"'}],
       }
     ],
+    expectedConfig: {
+      label: SUPPORTED_LABEL,
+      initDataTypes: ['cenc'],
+      videoCapabilities: [{contentType: 'video/mp4; codecs="avc1.42E01E"'}],
+    },
     shouldPass: true,
   },
   {
@@ -239,8 +354,8 @@ var tests = [
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        videoType: 'video/mp4; codecs="bogus"',
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4; codecs="bogus"'}],
       }
     ],
     shouldPass: false,
@@ -250,8 +365,8 @@ var tests = [
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        videoType: 'video/mp4; codecs="avc1.42E01E,mp4a.40.2"',
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4; codecs="avc1.42E01E,mp4a.40.2"'}],
       }
     ],
     shouldPass: false,
@@ -261,11 +376,18 @@ var tests = [
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'cenc',
-        videoType: 'video/mp4; codecs="avc1.42E01E"',
-        audioType: 'audio/mp4; codecs="mp4a.40.2"',
+        label: SUPPORTED_LABEL,
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4; codecs="avc1.42E01E"'}],
+        audioCapabilities: [{contentType: 'audio/mp4; codecs="mp4a.40.2"'}],
       }
     ],
+    expectedConfig: {
+      label: SUPPORTED_LABEL,
+      initDataTypes: ['cenc'],
+      videoCapabilities: [{contentType: 'video/mp4; codecs="avc1.42E01E"'}],
+      audioCapabilities: [{contentType: 'audio/mp4; codecs="mp4a.40.2"'}],
+    },
     shouldPass: true,
   },
   {
@@ -273,8 +395,8 @@ var tests = [
     keySystem: CLEARKEY_ID,
     options: [
       {
-        initDataType: 'webm',
-        videoType: 'video/webm',
+        initDataTypes: ['webm'],
+        videoCapabilities: [{contentType: 'video/webm'}],
       }
     ],
     shouldPass: false,
@@ -282,23 +404,103 @@ var tests = [
   {
     name: "CDM version less than",
     keySystem: CLEARKEY_ID + ".0",
+    options: [
+      {
+        label: SUPPORTED_LABEL,
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4'}],
+      }
+    ],
+    expectedConfig: {
+      label: SUPPORTED_LABEL,
+      initDataTypes: ['cenc'],
+      videoCapabilities: [{contentType: 'video/mp4'}],
+    },
     shouldPass: true
   },
   {
     name: "CDM version equal to",
     keySystem: CLEARKEY_ID + ".1",
+    options: [
+      {
+        label: SUPPORTED_LABEL,
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4'}],
+      }
+    ],
+    expectedConfig: {
+      label: SUPPORTED_LABEL,
+      initDataTypes: ['cenc'],
+      videoCapabilities: [{contentType: 'video/mp4'}],
+    },
     shouldPass: true
   },
   {
     name: "CDM version greater than",
     keySystem: CLEARKEY_ID + ".2",
+    options: [
+      {
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4'}],
+      }
+    ],
     shouldPass: false
   },
   {
     name: "Non-whole number CDM version",
     keySystem: CLEARKEY_ID + ".0.1",
+    options: [
+      {
+        initDataTypes: ['cenc'],
+        videoCapabilities: [{contentType: 'video/mp4'}],
+      }
+    ],
     shouldPass: false
   },
+
+  // Test legacy support. Remove when we remove backwards compatibility.
+  {
+    name: 'Legacy CENC',
+    keySystem: CLEARKEY_ID,
+    options: [
+      {
+        initDataType: 'cenc',
+      }
+    ],
+    expectedConfig: {
+      label: ''
+    },
+    shouldPass: true,
+  },
+  {
+    name: 'Legacy CENC + MP4 video',
+    keySystem: CLEARKEY_ID,
+    options: [
+      {
+        initDataType: 'cenc',
+        videoType: 'video/mp4; codecs="avc1.42E01E"',
+      }
+    ],
+    expectedConfig: {
+      label: ''
+    },
+    shouldPass: true,
+  },
+  {
+    name: 'Legacy CENC + MP4 video + MP4 audio',
+    keySystem: CLEARKEY_ID,
+    options: [
+      {
+        initDataType: 'cenc',
+        videoType: 'video/mp4; codecs="avc1.42E01E"',
+        audioType: 'audio/mp4; codecs="mp4a.40.2"',
+      }
+    ],
+    expectedConfig: {
+      label: ''
+    },
+    shouldPass: true,
+  },
 ];
 
 function beginTest() {
diff --git a/dom/media/test/test_eme_request_notifications.html b/dom/media/test/test_eme_request_notifications.html
index 2be826ea162..91c38400b1a 100644
--- a/dom/media/test/test_eme_request_notifications.html
+++ b/dom/media/test/test_eme_request_notifications.html
@@ -1,109 +1,109 @@
-<!DOCTYPE HTML>
-<html>
-<head>
-  <title>Test Encrypted Media Extensions</title>
-  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
-  <script type="text/javascript" src="manifest.js"></script>
-  <script type="text/javascript" src="eme.js"></script>
-</head>
-<body>
-<pre id="test">
-<script class="testbody" type="text/javascript">
-var manager = new MediaTestManager;
-
-var observedStatus = "nothing";
-
-var observer = function(subject, topic, data) {
-  observedStatus = JSON.parse(data).status;
-  info("Observed: " + observedStatus);  
-};
-SpecialPowers.Services.obs.addObserver(observer, "mediakeys-request", false);
-
-SimpleTest.registerCleanupFunction(function() {
-  SpecialPowers.Services.obs.removeObserver(observer, "mediakeys-request");
-});
-
-function SetPrefs(prefs) {
-  return new Promise(function(resolve, reject) {
-    SpecialPowers.pushPrefEnv({"set": prefs}, function() { resolve(); });
-  });
-}
-
-function Test(test) {
-  var p = test.prefs ? SetPrefs(test.prefs) : Promise.resolve();
-  observedStatus = "nothing";
-  var name = "'" + test.keySystem + "'";
-  return p.then(function() {
-    return new Promise(function(resolve, reject) {
-      navigator.requestMediaKeySystemAccess(test.keySystem)
-      .then(
-        function(keySystemAccess) {
-          return keySystemAccess.createMediaKeys();
-        })
-      .then(
-        function(mediaKeys) {
-          ok(test.shouldPass, name + " passed and was expected to " + (test.shouldPass ? "pass" : "fail"));
-          is(observedStatus, test.expectedStatus, name + " observer service result");
-          resolve();
-        }
-      )
-      .catch(
-        function() {
-          ok(!test.shouldPass, name + " failed and was expected to " + (test.shouldPass ? "pass" : "fail"));
-          is(observedStatus, test.expectedStatus, name + " observer service result");
-          resolve();
-        }
-      );
-    });
-  });
-}
-
-const CLEARKEY_ID = 'org.w3.clearkey';
-
-var tests = [
-  {
-    keySystem: CLEARKEY_ID,
-    shouldPass: false,
-    expectedStatus: 'api-disabled',
-    prefs: [["media.eme.enabled", false], ["media.eme.clearkey.enabled", true]]
-  },
-  {
-    keySystem: CLEARKEY_ID,
-    shouldPass: false,
-    expectedStatus: 'cdm-disabled',
-    prefs: [["media.eme.enabled", true], ["media.eme.clearkey.enabled", false]]
-  },
-  {
-    keySystem: 'unsupported-keysystem',
-    shouldPass: false,
-    expectedStatus: 'cdm-not-supported'
-  },
-  {
-    keySystem: CLEARKEY_ID + '.10000' , // A stupendously high min CDM version, presumably not installed.
-    shouldPass: false,
-    expectedStatus: 'cdm-insufficient-version',
-    prefs: [["media.eme.enabled", true], ["media.eme.clearkey.enabled", true]]
-  },
-  {
-    keySystem: CLEARKEY_ID,
-    shouldPass: true,
-    expectedStatus: 'cdm-created',
-    prefs: [["media.eme.enabled", true], ["media.eme.clearkey.enabled", true]]
-  },
-];
-
-SetupEMEPref(function() {
-  tests.reduce(function(p,c,i,array) {
-    return p.then(function() { return Test(c); });
-  }, Promise.resolve()).then(SimpleTest.finish);
-});
-
-
-SimpleTest.waitForExplicitFinish();
-
-</script>
-</pre>
-</body>
-</html>
-
+<!DOCTYPE HTML>
+<html>
+<head>
+  <title>Test Encrypted Media Extensions</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+  <script type="text/javascript" src="manifest.js"></script>
+  <script type="text/javascript" src="eme.js"></script>
+</head>
+<body>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+var manager = new MediaTestManager;
+
+var observedStatus = "nothing";
+
+var observer = function(subject, topic, data) {
+  observedStatus = JSON.parse(data).status;
+  info("Observed: " + observedStatus);
+};
+SpecialPowers.Services.obs.addObserver(observer, "mediakeys-request", false);
+
+SimpleTest.registerCleanupFunction(function() {
+  SpecialPowers.Services.obs.removeObserver(observer, "mediakeys-request");
+});
+
+function SetPrefs(prefs) {
+  return new Promise(function(resolve, reject) {
+    SpecialPowers.pushPrefEnv({"set": prefs}, function() { resolve(); });
+  });
+}
+
+function Test(test) {
+  var p = test.prefs ? SetPrefs(test.prefs) : Promise.resolve();
+  observedStatus = "nothing";
+  var name = "'" + test.keySystem + "'";
+  return p.then(function() {
+    return new Promise(function(resolve, reject) {
+      navigator.requestMediaKeySystemAccess(test.keySystem, [{initDataTypes:["cenc"]}])
+      .then(
+        function(keySystemAccess) {
+          return keySystemAccess.createMediaKeys();
+        })
+      .then(
+        function(mediaKeys) {
+          ok(test.shouldPass, name + " passed and was expected to " + (test.shouldPass ? "pass" : "fail"));
+          is(observedStatus, test.expectedStatus, name + " observer service result");
+          resolve();
+        }
+      )
+      .catch(
+        function() {
+          ok(!test.shouldPass, name + " failed and was expected to " + (test.shouldPass ? "pass" : "fail"));
+          is(observedStatus, test.expectedStatus, name + " observer service result");
+          resolve();
+        }
+      );
+    });
+  });
+}
+
+const CLEARKEY_ID = 'org.w3.clearkey';
+
+var tests = [
+  {
+    keySystem: CLEARKEY_ID,
+    shouldPass: false,
+    expectedStatus: 'api-disabled',
+    prefs: [["media.eme.enabled", false], ["media.eme.clearkey.enabled", true]]
+  },
+  {
+    keySystem: CLEARKEY_ID,
+    shouldPass: false,
+    expectedStatus: 'cdm-disabled',
+    prefs: [["media.eme.enabled", true], ["media.eme.clearkey.enabled", false]]
+  },
+  {
+    keySystem: 'unsupported-keysystem',
+    shouldPass: false,
+    expectedStatus: 'cdm-not-supported'
+  },
+  {
+    keySystem: CLEARKEY_ID + '.10000' , // A stupendously high min CDM version, presumably not installed.
+    shouldPass: false,
+    expectedStatus: 'cdm-insufficient-version',
+    prefs: [["media.eme.enabled", true], ["media.eme.clearkey.enabled", true]]
+  },
+  {
+    keySystem: CLEARKEY_ID,
+    shouldPass: true,
+    expectedStatus: 'cdm-created',
+    prefs: [["media.eme.enabled", true], ["media.eme.clearkey.enabled", true]]
+  },
+];
+
+SetupEMEPref(function() {
+  tests.reduce(function(p,c,i,array) {
+    return p.then(function() { return Test(c); });
+  }, Promise.resolve()).then(SimpleTest.finish);
+});
+
+
+SimpleTest.waitForExplicitFinish();
+
+</script>
+</pre>
+</body>
+</html>
+
diff --git a/dom/plugins/base/nsNPAPIPlugin.cpp b/dom/plugins/base/nsNPAPIPlugin.cpp
index 8882916b4f4..7caab1bc04e 100644
--- a/dom/plugins/base/nsNPAPIPlugin.cpp
+++ b/dom/plugins/base/nsNPAPIPlugin.cpp
@@ -693,7 +693,6 @@ AsyncCallbackAutoLock::~AsyncCallbackAutoLock()
   }
 }
 
-
 NPP NPPStack::sCurrentNPP = nullptr;
 
 const char *
@@ -744,7 +743,6 @@ _geturl(NPP npp, const char* relativeURL, const char* target)
       (strncmp(relativeURL, "ftp:", 4) != 0)) {
     nsNPAPIPluginInstance *inst = (nsNPAPIPluginInstance *) npp->ndata;
 
-
     const char *name = nullptr;
     RefPtr<nsPluginHost> host = nsPluginHost::GetInst();
     host->GetPluginName(inst, &name);
@@ -1958,9 +1956,7 @@ _getvalue(NPP npp, NPNVariable variable, void *result)
         return NPERR_NO_ERROR;
       }
     }
-    else {
-      return NPERR_GENERIC_ERROR;
-    }
+    return NPERR_GENERIC_ERROR;
   }
 
 #ifndef NP_NO_QUICKDRAW
@@ -2189,14 +2185,13 @@ _getvalue(NPP npp, NPNVariable variable, void *result)
 
   // we no longer hand out any XPCOM objects
   case NPNVDOMElement:
-    // fall through
   case NPNVDOMWindow:
-    // fall through
   case NPNVserviceManager:
     // old XPCOM objects, no longer supported, but null out the out
     // param to avoid crashing plugins that still try to use this.
     *(nsISupports**)result = nullptr;
-    // fall through
+    MOZ_FALLTHROUGH;
+
   default:
     NPN_PLUGIN_LOG(PLUGIN_LOG_NORMAL, ("NPN_getvalue unhandled get value: %d\n", variable));
     return NPERR_GENERIC_ERROR;
diff --git a/dom/plugins/base/nsPluginInstanceOwner.cpp b/dom/plugins/base/nsPluginInstanceOwner.cpp
index 1cc5f80cb89..2b423d2fe18 100644
--- a/dom/plugins/base/nsPluginInstanceOwner.cpp
+++ b/dom/plugins/base/nsPluginInstanceOwner.cpp
@@ -3030,11 +3030,8 @@ NS_IMETHODIMP nsPluginInstanceOwner::CreateWidget(void)
 #ifndef XP_MACOSX
       // If we're running in the content process, we need a remote widget created in chrome.
       if (XRE_IsContentProcess()) {
-        nsCOMPtr<nsIDOMWindow> window = doc->GetWindow();
-        if (window) {
-          nsCOMPtr<nsIDOMWindow> topWindow;
-          window->GetTop(getter_AddRefs(topWindow));
-          if (topWindow) {
+        if (nsCOMPtr<nsPIDOMWindow> window = doc->GetWindow()) {
+          if (nsCOMPtr<nsPIDOMWindow> topWindow = window->GetTop()) {
             dom::TabChild* tc = dom::TabChild::GetFrom(topWindow);
             if (tc) {
               // This returns a PluginWidgetProxy which remotes a number of calls.
diff --git a/dom/plugins/ipc/PluginInstanceChild.cpp b/dom/plugins/ipc/PluginInstanceChild.cpp
index f6dee021c5a..5802dc3cd67 100644
--- a/dom/plugins/ipc/PluginInstanceChild.cpp
+++ b/dom/plugins/ipc/PluginInstanceChild.cpp
@@ -502,6 +502,7 @@ PluginInstanceChild::NPN_GetValue(NPNVariable aVar,
     case NPNVSupportsXEmbedBool:
     case NPNVSupportsWindowless:
         NS_NOTREACHED("NPNVariable should be handled in PluginModuleChild.");
+        MOZ_FALLTHROUGH;
 #endif
 
     default:
@@ -510,7 +511,6 @@ PluginInstanceChild::NPN_GetValue(NPNVariable aVar,
                 (int) aVar, NPNVariableToString(aVar)));
         return NPERR_GENERIC_ERROR;
     }
-
 }
 
 #ifdef MOZ_WIDGET_COCOA
@@ -2313,7 +2313,6 @@ PluginInstanceChild::EnumThreadWindowsCallback(HWND hWnd,
     return TRUE;
 }
 
-
 void
 PluginInstanceChild::SetupFlashMsgThrottle()
 {
@@ -2610,7 +2609,6 @@ StreamNotifyChild::ActorDestroy(ActorDestroyReason why)
     }
 }
 
-
 void
 StreamNotifyChild::SetAssociatedStream(BrowserStreamChild* bs)
 {
diff --git a/dom/push/PushServiceWebSocket.jsm b/dom/push/PushServiceWebSocket.jsm
index dc0cd8e1f2e..1fb226502c0 100644
--- a/dom/push/PushServiceWebSocket.jsm
+++ b/dom/push/PushServiceWebSocket.jsm
@@ -1135,14 +1135,6 @@ this.PushServiceWebSocket = {
       data.uaid = this._UAID;
     }
 
-    function sendHelloMessage(ids) {
-      // On success, ids is an array, on error its not.
-      data.channelIDs = ids.map ?
-                           ids.map(function(el) { return el.channelID; }) : [];
-      this._wsSendMessage(data);
-      this._currentState = STATE_WAITING_FOR_HELLO;
-    }
-
     this._networkInfo.getNetworkState((networkState) => {
       if (networkState.ip) {
         // Opening an available UDP port.
@@ -1161,9 +1153,8 @@ this.PushServiceWebSocket = {
         };
       }
 
-      this._mainPushService.getAllUnexpired()
-        .then(sendHelloMessage.bind(this),
-              sendHelloMessage.bind(this));
+      this._wsSendMessage(data);
+      this._currentState = STATE_WAITING_FOR_HELLO;
     });
   },
 
diff --git a/dom/push/test/lifetime_worker.js b/dom/push/test/lifetime_worker.js
index fbba885b5b2..32ab188dd74 100644
--- a/dom/push/test/lifetime_worker.js
+++ b/dom/push/test/lifetime_worker.js
@@ -7,13 +7,15 @@ onfetch = function(event) {
     return;
   }
 
-  if (!event.client) {
-    dump("ERROR: no client to post the message to!\n");
-    dump("request.url=" + event.request.url + "\n");
-    return;
-  }
-
-  event.client.postMessage({type: "fetch", state: state});
+  var currentState = state;
+  event.waitUntil(
+    clients.matchAll()
+           .then(clients => {
+             clients.forEach(client => {
+               client.postMessage({type: "fetch", state: currentState});
+             });
+           })
+  );
 
   if (event.request.url.indexOf("update") >= 0) {
     state = "update";
diff --git a/dom/push/test/xpcshell/test_notification_ack.js b/dom/push/test/xpcshell/test_notification_ack.js
index ca713b8af6c..2c09d751c67 100644
--- a/dom/push/test/xpcshell/test_notification_ack.js
+++ b/dom/push/test/xpcshell/test_notification_ack.js
@@ -65,11 +65,6 @@ add_task(function* test_notification_ack() {
         onHello(request) {
           equal(request.uaid, userAgentID,
             'Should send matching device IDs in handshake');
-          deepEqual(request.channelIDs.sort(), [
-            '21668e05-6da8-42c9-b8ab-9cc3f4d5630c',
-            '5477bfda-22db-45d4-9614-fee369630260',
-            '9a5ff87f-47c9-4215-b2b8-0bdd38b4b305'
-          ], 'Should send matching channel IDs in handshake');
           this.serverSendMsg(JSON.stringify({
             messageType: 'hello',
             uaid: userAgentID,
diff --git a/dom/push/test/xpcshell/test_notification_data.js b/dom/push/test/xpcshell/test_notification_data.js
index c87fcbefb39..e5d0b15ece4 100644
--- a/dom/push/test/xpcshell/test_notification_data.js
+++ b/dom/push/test/xpcshell/test_notification_data.js
@@ -99,11 +99,6 @@ add_task(function* test_notification_ack_data() {
         onHello(request) {
           equal(request.uaid, userAgentID,
             'Should send matching device IDs in handshake');
-          deepEqual(
-            request.channelIDs.sort(),
-            ['subscription1', 'subscription2', 'subscription3'],
-            'Should send matching channel IDs in handshake'
-          );
           this.serverSendMsg(JSON.stringify({
             messageType: 'hello',
             uaid: userAgentID,
diff --git a/dom/push/test/xpcshell/test_notification_error.js b/dom/push/test/xpcshell/test_notification_error.js
index 2b13bba0e25..400422a83b4 100644
--- a/dom/push/test/xpcshell/test_notification_error.js
+++ b/dom/push/test/xpcshell/test_notification_error.js
@@ -78,11 +78,6 @@ add_task(function* test_notification_error() {
     makeWebSocket(uri) {
       return new MockWebSocket(uri, {
         onHello(request) {
-          deepEqual(request.channelIDs.sort(), [
-            '3c3930ba-44de-40dc-a7ca-8a133ec1a866',
-            'b63f7bef-0a0d-4236-b41e-086a69dfd316',
-            'f04f1e46-9139-4826-b2d1-9411b0821283'
-          ], 'Wrong channel list');
           this.serverSendMsg(JSON.stringify({
             messageType: 'hello',
             status: 200,
diff --git a/dom/push/test/xpcshell/test_quota_exceeded.js b/dom/push/test/xpcshell/test_quota_exceeded.js
index 52265e5a665..00a9fb03964 100644
--- a/dom/push/test/xpcshell/test_quota_exceeded.js
+++ b/dom/push/test/xpcshell/test_quota_exceeded.js
@@ -96,10 +96,6 @@ add_task(function* test_expiration_origin_threshold() {
     makeWebSocket(uri) {
       return new MockWebSocket(uri, {
         onHello(request) {
-          deepEqual(request.channelIDs.sort(), [
-            '46cc6f6a-c106-4ffa-bb7c-55c60bd50c41',
-            'eb33fc90-c883-4267-b5cb-613969e8e349',
-          ], 'Wrong active registrations in handshake');
           this.serverSendMsg(JSON.stringify({
             messageType: 'hello',
             status: 200,
diff --git a/dom/push/test/xpcshell/test_quota_observer.js b/dom/push/test/xpcshell/test_quota_observer.js
index d0cf2563cde..32209cf0095 100644
--- a/dom/push/test/xpcshell/test_quota_observer.js
+++ b/dom/push/test/xpcshell/test_quota_observer.js
@@ -64,9 +64,6 @@ add_task(function* test_expiration_history_observer() {
     makeWebSocket(uri) {
       return new MockWebSocket(uri, {
         onHello(request) {
-          deepEqual(request.channelIDs, [
-            '379c0668-8323-44d2-a315-4ee83f1a9ee9',
-          ], 'Should not include expired channel IDs');
           this.serverSendMsg(JSON.stringify({
             messageType: 'hello',
             status: 200,
diff --git a/dom/push/test/xpcshell/test_register_timeout.js b/dom/push/test/xpcshell/test_register_timeout.js
index d0a084198f0..7c558f3cfa2 100644
--- a/dom/push/test/xpcshell/test_register_timeout.js
+++ b/dom/push/test/xpcshell/test_register_timeout.js
@@ -37,23 +37,14 @@ add_task(function* test_register_timeout() {
     makeWebSocket(uri) {
       return new MockWebSocket(uri, {
         onHello(request) {
-          switch (handshakes) {
-          case 0:
+          if (handshakes === 0) {
             equal(request.uaid, null, 'Should not include device ID');
-            deepEqual(request.channelIDs, [],
-              'Should include empty channel list');
-            break;
-
-          case 1:
+          } else if (handshakes === 1) {
             // Should use the previously-issued device ID when reconnecting,
             // but should not include the timed-out channel ID.
             equal(request.uaid, userAgentID,
               'Should include device ID on reconnect');
-            deepEqual(request.channelIDs, [],
-              'Should not include failed channel ID');
-            break;
-
-          default:
+          } else {
             ok(false, 'Unexpected reconnect attempt ' + handshakes);
           }
           handshakes++;
diff --git a/dom/push/test/xpcshell/test_registration_success.js b/dom/push/test/xpcshell/test_registration_success.js
index d7c73840800..e4c81f3b6e6 100644
--- a/dom/push/test/xpcshell/test_registration_success.js
+++ b/dom/push/test/xpcshell/test_registration_success.js
@@ -51,11 +51,6 @@ add_task(function* test_registration_success() {
       return new MockWebSocket(uri, {
         onHello(request) {
           equal(request.uaid, userAgentID, 'Wrong device ID in handshake');
-          deepEqual(request.channelIDs.sort(), [
-            'b1cf38c9-6836-4d29-8a30-a3e98d59b728',
-            'bf001fe0-2684-42f2-bc4d-a3e14b11dd5b',
-            'f6edfbcd-79d6-49b8-9766-48b9dcfeff0f',
-          ], 'Wrong channel list in handshake');
           this.serverSendMsg(JSON.stringify({
             messageType: 'hello',
             status: 200,
diff --git a/dom/push/test/xpcshell/test_webapps_cleardata.js b/dom/push/test/xpcshell/test_webapps_cleardata.js
index 9a6e6fb0a3c..a985a95ed91 100644
--- a/dom/push/test/xpcshell/test_webapps_cleardata.js
+++ b/dom/push/test/xpcshell/test_webapps_cleardata.js
@@ -6,8 +6,6 @@
 const {PushDB, PushService, PushServiceWebSocket} = serviceExports;
 
 const userAgentID = 'bd744428-f125-436a-b6d0-dd0c9845837f';
-const channelIDs = ['0ef2ad4a-6c49-41ad-af6e-95d2425276bf', '4818b54a-97c5-4277-ad5d-0bfe630e4e50'];
-var channelIDCounter = 0;
 
 function run_test() {
   do_get_profile();
diff --git a/dom/simplepush/PushService.jsm b/dom/simplepush/PushService.jsm
index 50d5c74deef..a72d7c1ccb6 100644
--- a/dom/simplepush/PushService.jsm
+++ b/dom/simplepush/PushService.jsm
@@ -1542,14 +1542,6 @@ this.PushService = {
     if (this._UAID)
       data["uaid"] = this._UAID;
 
-    function sendHelloMessage(ids) {
-      // On success, ids is an array, on error its not.
-      data["channelIDs"] = ids.map ?
-                           ids.map(function(el) { return el.channelID; }) : [];
-      this._wsSendMessage(data);
-      this._currentState = STATE_WAITING_FOR_HELLO;
-    }
-
     this._getNetworkState((networkState) => {
       if (networkState.ip) {
         // Opening an available UDP port.
@@ -1568,8 +1560,8 @@ this.PushService = {
         };
       }
 
-      this._db.getAllChannelIDs(sendHelloMessage.bind(this),
-                                sendHelloMessage.bind(this));
+      this._wsSendMessage(data);
+      this._currentState = STATE_WAITING_FOR_HELLO;
     });
   },
 
diff --git a/dom/system/nsDeviceSensors.cpp b/dom/system/nsDeviceSensors.cpp
index 801f915ad5a..28845614b8d 100644
--- a/dom/system/nsDeviceSensors.cpp
+++ b/dom/system/nsDeviceSensors.cpp
@@ -217,15 +217,12 @@ nsDeviceSensors::Notify(const mozilla::hal::SensorData& aSensorData)
         continue;
     }
 
-    nsCOMPtr<nsIDOMDocument> domdoc;
-    windowListeners[i]->GetDocument(getter_AddRefs(domdoc));
-
-    if (domdoc) {
+    if (nsCOMPtr<nsIDOMDocument> domDoc = do_QueryInterface(pwindow->GetDoc())) {
       nsCOMPtr<mozilla::dom::EventTarget> target = do_QueryInterface(windowListeners[i]);
       if (type == nsIDeviceSensorData::TYPE_ACCELERATION ||
         type == nsIDeviceSensorData::TYPE_LINEAR_ACCELERATION ||
         type == nsIDeviceSensorData::TYPE_GYROSCOPE)
-        FireDOMMotionEvent(domdoc, target, type, x, y, z);
+        FireDOMMotionEvent(domDoc, target, type, x, y, z);
       else if (type == nsIDeviceSensorData::TYPE_ORIENTATION)
         FireDOMOrientationEvent(target, x, y, z);
       else if (type == nsIDeviceSensorData::TYPE_PROXIMITY)
diff --git a/dom/webidl/Client.webidl b/dom/webidl/Client.webidl
index a2111a8d612..45027bd71d0 100644
--- a/dom/webidl/Client.webidl
+++ b/dom/webidl/Client.webidl
@@ -10,8 +10,9 @@
 
 [Exposed=ServiceWorker]
 interface Client {
-  readonly attribute DOMString id;
   readonly attribute USVString url;
+  readonly attribute FrameType frameType;
+  readonly attribute DOMString id;
 
   [Throws]
   void postMessage(any message, optional sequence<Transferable> transfer);
@@ -21,9 +22,8 @@ interface Client {
 interface WindowClient : Client {
   readonly attribute VisibilityState visibilityState;
   readonly attribute boolean focused;
-  readonly attribute FrameType frameType;
 
-  [Throws]
+  [Throws, NewObject]
   Promise<WindowClient> focus();
 };
 
diff --git a/dom/webidl/Clients.webidl b/dom/webidl/Clients.webidl
index c3d97d266cf..edcb40c910a 100644
--- a/dom/webidl/Clients.webidl
+++ b/dom/webidl/Clients.webidl
@@ -11,11 +11,12 @@
 [Exposed=ServiceWorker]
 interface Clients {
   // The objects returned will be new instances every time
-  [Throws]
+  [NewObject]
   Promise<sequence<Client>?> matchAll(optional ClientQueryOptions options);
-  [Throws, Func="mozilla::dom::workers::ServiceWorkerGlobalScope::OpenWindowEnabled"]
+  [NewObject,
+   Func="mozilla::dom::workers::ServiceWorkerGlobalScope::OpenWindowEnabled"]
   Promise<WindowClient> openWindow(USVString url);
-  [Throws]
+  [NewObject]
   Promise<void> claim();
 };
 
diff --git a/dom/webidl/Element.webidl b/dom/webidl/Element.webidl
index 978cf9b6e59..0e572cd875c 100644
--- a/dom/webidl/Element.webidl
+++ b/dom/webidl/Element.webidl
@@ -199,11 +199,13 @@ partial interface Element {
   readonly attribute long clientHeight;
 
   // Mozilla specific stuff
-  /* The maximum offset that the element can be scrolled to
+  /* The minimum/maximum offset that the element can be scrolled to
      (i.e., the value that scrollLeft/scrollTop would be clamped to if they were
      set to arbitrarily large values. */
-  readonly attribute long scrollTopMax;
-  readonly attribute long scrollLeftMax;
+  [ChromeOnly] readonly attribute long scrollTopMin;
+               readonly attribute long scrollTopMax;
+  [ChromeOnly] readonly attribute long scrollLeftMin;
+               readonly attribute long scrollLeftMax;
 };
 
 // http://dvcs.w3.org/hg/undomanager/raw-file/tip/undomanager.html
diff --git a/dom/webidl/FetchEvent.webidl b/dom/webidl/FetchEvent.webidl
index a5a7f8e3540..105ae12c02e 100644
--- a/dom/webidl/FetchEvent.webidl
+++ b/dom/webidl/FetchEvent.webidl
@@ -10,11 +10,8 @@
 [Constructor(DOMString type, optional FetchEventInit eventInitDict),
  Func="mozilla::dom::workers::ServiceWorkerVisible",
  Exposed=(ServiceWorker)]
-interface FetchEvent : Event {
-  readonly attribute Request request;
-
-  // https://github.com/slightlyoff/ServiceWorker/issues/631
-  readonly attribute Client? client; // The window issuing the request.
+interface FetchEvent : ExtendableEvent {
+  [SameObject] readonly attribute Request? request;
   readonly attribute boolean isReload;
 
   [Throws]
@@ -23,6 +20,5 @@ interface FetchEvent : Event {
 
 dictionary FetchEventInit : EventInit {
   Request request;
-  Client client;
-  boolean isReload;
+  boolean isReload = false;
 };
diff --git a/dom/webidl/MediaKeySystemAccess.webidl b/dom/webidl/MediaKeySystemAccess.webidl
index 33390fef246..dc8021279e4 100644
--- a/dom/webidl/MediaKeySystemAccess.webidl
+++ b/dom/webidl/MediaKeySystemAccess.webidl
@@ -10,25 +10,31 @@
  * W3C liability, trademark and document use rules apply.
  */
 
-enum MediaKeysRequirement {
-  "required",
-  "optional",
-  "disallowed"
+dictionary MediaKeySystemMediaCapability {
+   DOMString contentType = "";
+   // TODO: robustness
 };
 
-dictionary MediaKeySystemOptions {
+dictionary MediaKeySystemConfiguration {
+  DOMString                               label = "";
+  sequence<DOMString>                     initDataTypes;
+  sequence<MediaKeySystemMediaCapability> audioCapabilities;
+  sequence<MediaKeySystemMediaCapability> videoCapabilities;
+
+   // TODO: distinctiveIdentifier, persistentState, sessionTypes  
+  
+  // For backwards compatibility with implementations using old
+  // MediaKeySystemOptions paradigm...
   DOMString            initDataType = "";
   DOMString            audioType = "";
-  DOMString            audioCapability = "";
   DOMString            videoType = "";
-  DOMString            videoCapability = "";
-  MediaKeysRequirement uniqueidentifier = "optional";
-  MediaKeysRequirement stateful = "optional";
 };
 
 [Pref="media.eme.apiVisible"]
 interface MediaKeySystemAccess {
   readonly    attribute DOMString keySystem;
   [NewObject]
+  MediaKeySystemConfiguration getConfiguration();
+  [NewObject]
   Promise<MediaKeys> createMediaKeys();
 };
diff --git a/dom/webidl/Navigator.webidl b/dom/webidl/Navigator.webidl
index f03aed9e6e0..ef76948cf22 100644
--- a/dom/webidl/Navigator.webidl
+++ b/dom/webidl/Navigator.webidl
@@ -447,7 +447,7 @@ partial interface Navigator {
   [Pref="media.eme.apiVisible", NewObject]
   Promise<MediaKeySystemAccess>
   requestMediaKeySystemAccess(DOMString keySystem,
-                              optional sequence<MediaKeySystemOptions> supportedConfigurations);
+                              sequence<MediaKeySystemConfiguration> supportedConfigurations);
 };
 #endif
 
diff --git a/dom/webidl/ServiceWorkerContainer.webidl b/dom/webidl/ServiceWorkerContainer.webidl
index 080896f02ab..58a73c4ed67 100644
--- a/dom/webidl/ServiceWorkerContainer.webidl
+++ b/dom/webidl/ServiceWorkerContainer.webidl
@@ -30,7 +30,6 @@ interface ServiceWorkerContainer : EventTarget {
   Promise<sequence<ServiceWorkerRegistration>> getRegistrations();
 
   attribute EventHandler oncontrollerchange;
-  attribute EventHandler onreloadpage;
   attribute EventHandler onerror;
   attribute EventHandler onmessage;
 };
diff --git a/dom/webidl/ServiceWorkerGlobalScope.webidl b/dom/webidl/ServiceWorkerGlobalScope.webidl
index 1f350551875..8902c467626 100644
--- a/dom/webidl/ServiceWorkerGlobalScope.webidl
+++ b/dom/webidl/ServiceWorkerGlobalScope.webidl
@@ -13,10 +13,10 @@
 [Global=(Worker,ServiceWorker),
  Exposed=ServiceWorker]
 interface ServiceWorkerGlobalScope : WorkerGlobalScope {
-  readonly attribute Clients clients;
-  readonly attribute ServiceWorkerRegistration registration;
+  [SameObject] readonly attribute Clients clients;
+  [SameObject] readonly attribute ServiceWorkerRegistration registration;
 
-  [Throws]
+  [Throws, NewObject]
   Promise<boolean> skipWaiting();
 
   attribute EventHandler oninstall;
@@ -24,8 +24,6 @@ interface ServiceWorkerGlobalScope : WorkerGlobalScope {
 
   [Func="mozilla::dom::workers::ServiceWorkerGlobalScope::InterceptionEnabled"]
   attribute EventHandler onfetch;
-  attribute EventHandler onbeforeevicted;
-  attribute EventHandler onevicted;
 
   // The event.source of these MessageEvents are instances of Client
   attribute EventHandler onmessage;
diff --git a/dom/webidl/Window.webidl b/dom/webidl/Window.webidl
index e6c4b693fd3..704c65636d3 100644
--- a/dom/webidl/Window.webidl
+++ b/dom/webidl/Window.webidl
@@ -266,7 +266,7 @@ Window implements WindowModal;
 
 // https://slightlyoff.github.io/ServiceWorker/spec/service_worker/index.html#self-caches
 partial interface Window {
-[Throws, Func="mozilla::dom::cache::CacheStorage::PrefEnabled"]
+[Throws, Func="mozilla::dom::cache::CacheStorage::PrefEnabled", SameObject]
 readonly attribute CacheStorage caches;
 };
 
@@ -302,6 +302,8 @@ partial interface Window {
 
   /* The maximum offset that the window can be scrolled to
      (i.e., the document width/height minus the scrollport width/height) */
+  [ChromeOnly, Throws]  readonly attribute long   scrollMinX;
+  [ChromeOnly, Throws]  readonly attribute long   scrollMinY;
   [Replaceable, Throws] readonly attribute long   scrollMaxX;
   [Replaceable, Throws] readonly attribute long   scrollMaxY;
 
diff --git a/dom/webidl/WorkerGlobalScope.webidl b/dom/webidl/WorkerGlobalScope.webidl
index f56eb40802a..3ea893d73a7 100644
--- a/dom/webidl/WorkerGlobalScope.webidl
+++ b/dom/webidl/WorkerGlobalScope.webidl
@@ -40,7 +40,7 @@ partial interface WorkerGlobalScope {
 
 // https://slightlyoff.github.io/ServiceWorker/spec/service_worker/index.html#self-caches
 partial interface WorkerGlobalScope {
-[Throws, Func="mozilla::dom::cache::CacheStorage::PrefEnabled"]
+[Throws, Func="mozilla::dom::cache::CacheStorage::PrefEnabled", SameObject]
 readonly attribute CacheStorage caches;
 };
 
diff --git a/dom/workers/RuntimeService.cpp b/dom/workers/RuntimeService.cpp
index 5285ea9805f..cf36d775eb3 100644
--- a/dom/workers/RuntimeService.cpp
+++ b/dom/workers/RuntimeService.cpp
@@ -122,10 +122,6 @@ static_assert(MAX_WORKERS_PER_DOMAIN >= 1,
 #define CC_REQUEST_OBSERVER_TOPIC "child-cc-request"
 #define MEMORY_PRESSURE_OBSERVER_TOPIC "memory-pressure"
 
-#define PREF_GENERAL_APPNAME_OVERRIDE "general.appname.override"
-#define PREF_GENERAL_APPVERSION_OVERRIDE "general.appversion.override"
-#define PREF_GENERAL_PLATFORM_OVERRIDE "general.platform.override"
-
 #define BROADCAST_ALL_WORKERS(_func, ...)                                      \
   PR_BEGIN_MACRO                                                               \
     AssertIsOnMainThread();                                                    \
@@ -152,28 +148,6 @@ static_assert(MAX_WORKERS_PER_DOMAIN >= 1,
 #define PREF_MEM_OPTIONS_PREFIX "mem."
 #define PREF_GCZEAL "gcZeal"
 
-#if !(defined(DEBUG) || defined(MOZ_ENABLE_JS_DUMP))
-#define DUMP_CONTROLLED_BY_PREF 1
-#define PREF_DOM_WINDOW_DUMP_ENABLED "browser.dom.window.dump.enabled"
-#endif
-
-#define PREF_DOM_CACHES_ENABLED        "dom.caches.enabled"
-#define PREF_DOM_CACHES_TESTING_ENABLED "dom.caches.testing.enabled"
-#define PREF_WORKERS_PERFORMANCE_LOGGING_ENABLED "dom.performance.enable_user_timing_logging"
-#define PREF_DOM_WORKERNOTIFICATION_ENABLED  "dom.webnotifications.enabled"
-#define PREF_DOM_SERVICEWORKERNOTIFICATION_ENABLED  "dom.webnotifications.serviceworker.enabled"
-#define PREF_WORKERS_LATEST_JS_VERSION "dom.workers.latestJSVersion"
-#define PREF_INTL_ACCEPT_LANGUAGES     "intl.accept_languages"
-#define PREF_SERVICEWORKERS_ENABLED    "dom.serviceWorkers.enabled"
-#define PREF_SERVICEWORKERS_TESTING_ENABLED "dom.serviceWorkers.testing.enabled"
-#define PREF_INTERCEPTION_ENABLED      "dom.serviceWorkers.interception.enabled"
-#define PREF_INTERCEPTION_OPAQUE_ENABLED "dom.serviceWorkers.interception.opaque.enabled"
-#define PREF_OPEN_WINDOW_ENABLED       "dom.serviceWorkers.openWindow.enabled"
-#define PREF_PUSH_ENABLED              "dom.push.enabled"
-#define PREF_REQUESTCACHE_ENABLED      "dom.requestcache.enabled"
-#define PREF_REQUESTCONTEXT_ENABLED    "dom.requestcontext.enabled"
-#define PREF_OFFSCREENCANVAS_ENABLED   "gfx.offscreencanvas.enabled"
-
 namespace {
 
 const uint32_t kNoIndex = uint32_t(-1);
@@ -1183,7 +1157,7 @@ AppNameOverrideChanged(const char* /* aPrefName */, void* /* aClosure */)
   AssertIsOnMainThread();
 
   const nsAdoptingString& override =
-    mozilla::Preferences::GetString(PREF_GENERAL_APPNAME_OVERRIDE);
+    mozilla::Preferences::GetString("general.appname.override");
 
   RuntimeService* runtime = RuntimeService::GetService();
   if (runtime) {
@@ -1197,7 +1171,7 @@ AppVersionOverrideChanged(const char* /* aPrefName */, void* /* aClosure */)
   AssertIsOnMainThread();
 
   const nsAdoptingString& override =
-    mozilla::Preferences::GetString(PREF_GENERAL_APPVERSION_OVERRIDE);
+    mozilla::Preferences::GetString("general.appversion.override");
 
   RuntimeService* runtime = RuntimeService::GetService();
   if (runtime) {
@@ -1211,7 +1185,7 @@ PlatformOverrideChanged(const char* /* aPrefName */, void* /* aClosure */)
   AssertIsOnMainThread();
 
   const nsAdoptingString& override =
-    mozilla::Preferences::GetString(PREF_GENERAL_PLATFORM_OVERRIDE);
+    mozilla::Preferences::GetString("general.platform.override");
 
   RuntimeService* runtime = RuntimeService::GetService();
   if (runtime) {
@@ -1858,11 +1832,6 @@ RuntimeService::Init()
                            WORKER_DEFAULT_ALLOCATION_THRESHOLD);
   }
 
-// If dump is not controlled by pref, it's set to true.
-#ifndef DUMP_CONTROLLED_BY_PREF
-  sDefaultPreferences[WORKERPREF_DUMP] = true;
-#endif
-
   mIdleThreadTimer = do_CreateInstance(NS_TIMER_CONTRACTID);
   NS_ENSURE_STATE(mIdleThreadTimer);
 
@@ -1911,99 +1880,29 @@ RuntimeService::Init()
                                              LoadGCZealOptions,
                                              PREF_JS_OPTIONS_PREFIX PREF_GCZEAL,
                                              nullptr)) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                        LoadGCZealOptions,
-                                        PREF_WORKERS_OPTIONS_PREFIX PREF_GCZEAL,
-                                        nullptr)) ||
 #endif
-#if DUMP_CONTROLLED_BY_PREF
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_DOM_WINDOW_DUMP_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_DUMP))) ||
-#endif
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_DOM_CACHES_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_DOM_CACHES))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_DOM_WORKERNOTIFICATION_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_DOM_WORKERNOTIFICATION))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_DOM_SERVICEWORKERNOTIFICATION_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_DOM_SERVICEWORKERNOTIFICATION))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_SERVICEWORKERS_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_SERVICEWORKERS))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_INTERCEPTION_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_INTERCEPTION_ENABLED))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_OPEN_WINDOW_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_OPEN_WINDOW_ENABLED))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_INTERCEPTION_OPAQUE_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_INTERCEPTION_OPAQUE_ENABLED))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_DOM_CACHES_TESTING_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_DOM_CACHES_TESTING))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_WORKERS_PERFORMANCE_LOGGING_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_PERFORMANCE_LOGGING_ENABLED))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_SERVICEWORKERS_TESTING_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_SERVICEWORKERS_TESTING))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_PUSH_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_PUSH))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_REQUESTCACHE_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_REQUESTCACHE))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_REQUESTCONTEXT_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_REQUESTCONTEXT))) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                  WorkerPrefChanged,
-                                  PREF_OFFSCREENCANVAS_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_OFFSCREENCANVAS))) ||
-      NS_FAILED(Preferences::RegisterCallback(LoadRuntimeOptions,
-                                              PREF_JS_OPTIONS_PREFIX,
-                                              nullptr)) ||
+
+#define WORKER_SIMPLE_PREF(name, getter, NAME)                                \
+      NS_FAILED(Preferences::RegisterCallbackAndCall(                         \
+                  WorkerPrefChanged,                                          \
+                  name,                                                       \
+                  reinterpret_cast<void*>(WORKERPREF_##NAME))) ||
+#define WORKER_PREF(name, callback)                                           \
+      NS_FAILED(Preferences::RegisterCallbackAndCall(                         \
+                  callback,                                                   \
+                  name,                                                       \
+                  nullptr)) ||
+#include "WorkerPrefs.h"
+#undef WORKER_SIMPLE_PREF
+#undef WORKER_PREF
+
       NS_FAILED(Preferences::RegisterCallbackAndCall(
                                                    LoadRuntimeOptions,
                                                    PREF_WORKERS_OPTIONS_PREFIX,
                                                    nullptr)) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(PrefLanguagesChanged,
-                                                     PREF_INTL_ACCEPT_LANGUAGES,
-                                                     nullptr)) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                                  AppNameOverrideChanged,
-                                                  PREF_GENERAL_APPNAME_OVERRIDE,
-                                                  nullptr)) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                               AppVersionOverrideChanged,
-                                               PREF_GENERAL_APPVERSION_OVERRIDE,
-                                               nullptr)) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                                 PlatformOverrideChanged,
-                                                 PREF_GENERAL_PLATFORM_OVERRIDE,
-                                                 nullptr)) ||
-      NS_FAILED(Preferences::RegisterCallbackAndCall(
-                                                 JSVersionChanged,
-                                                 PREF_WORKERS_LATEST_JS_VERSION,
-                                                 nullptr))) {
+      NS_FAILED(Preferences::RegisterCallback(LoadRuntimeOptions,
+                                              PREF_JS_OPTIONS_PREFIX,
+                                              nullptr))) {
     NS_WARNING("Failed to register pref callbacks!");
   }
 
@@ -2153,97 +2052,32 @@ RuntimeService::Cleanup()
   NS_ASSERTION(!mWindowMap.Count(), "All windows should have been released!");
 
   if (mObserved) {
-    if (NS_FAILED(Preferences::UnregisterCallback(JSVersionChanged,
-                                                  PREF_WORKERS_LATEST_JS_VERSION,
-                                                  nullptr)) ||
-        NS_FAILED(Preferences::UnregisterCallback(AppNameOverrideChanged,
-                                                  PREF_GENERAL_APPNAME_OVERRIDE,
-                                                  nullptr)) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                               AppVersionOverrideChanged,
-                                               PREF_GENERAL_APPVERSION_OVERRIDE,
-                                               nullptr)) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                                 PlatformOverrideChanged,
-                                                 PREF_GENERAL_PLATFORM_OVERRIDE,
-                                                 nullptr)) ||
-        NS_FAILED(Preferences::UnregisterCallback(LoadRuntimeOptions,
+    if (NS_FAILED(Preferences::UnregisterCallback(LoadRuntimeOptions,
                                                   PREF_JS_OPTIONS_PREFIX,
                                                   nullptr)) ||
         NS_FAILED(Preferences::UnregisterCallback(LoadRuntimeOptions,
                                                   PREF_WORKERS_OPTIONS_PREFIX,
                                                   nullptr)) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_SERVICEWORKERS_TESTING_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_SERVICEWORKERS_TESTING))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_DOM_CACHES_TESTING_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_DOM_CACHES_TESTING))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_WORKERS_PERFORMANCE_LOGGING_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_PERFORMANCE_LOGGING_ENABLED))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_INTERCEPTION_OPAQUE_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_INTERCEPTION_OPAQUE_ENABLED))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_INTERCEPTION_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_INTERCEPTION_ENABLED))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_OPEN_WINDOW_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_OPEN_WINDOW_ENABLED))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_SERVICEWORKERS_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_SERVICEWORKERS))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_DOM_CACHES_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_DOM_CACHES))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_DOM_WORKERNOTIFICATION_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_DOM_WORKERNOTIFICATION))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_DOM_SERVICEWORKERNOTIFICATION_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_DOM_SERVICEWORKERNOTIFICATION))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_PUSH_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_PUSH))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_REQUESTCACHE_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_REQUESTCACHE))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_REQUESTCONTEXT_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_REQUESTCONTEXT))) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_OFFSCREENCANVAS_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_OFFSCREENCANVAS))) ||
-#if DUMP_CONTROLLED_BY_PREF
-        NS_FAILED(Preferences::UnregisterCallback(
-                                  WorkerPrefChanged,
-                                  PREF_DOM_WINDOW_DUMP_ENABLED,
-                                  reinterpret_cast<void *>(WORKERPREF_DUMP))) ||
-#endif
+
+#define WORKER_SIMPLE_PREF(name, getter, NAME)                                \
+      NS_FAILED(Preferences::UnregisterCallback(                              \
+                  WorkerPrefChanged,                                          \
+                  name,                                                       \
+                  reinterpret_cast<void*>(WORKERPREF_##NAME))) ||
+#define WORKER_PREF(name, callback)                                           \
+      NS_FAILED(Preferences::UnregisterCallback(                              \
+                  callback,                                                   \
+                  name,                                                       \
+                  nullptr)) ||
+#include "WorkerPrefs.h"
+#undef WORKER_SIMPLE_PREF
+#undef WORKER_PREF
+
 #ifdef JS_GC_ZEAL
         NS_FAILED(Preferences::UnregisterCallback(
                                              LoadGCZealOptions,
                                              PREF_JS_OPTIONS_PREFIX PREF_GCZEAL,
                                              nullptr)) ||
-        NS_FAILED(Preferences::UnregisterCallback(
-                                        LoadGCZealOptions,
-                                        PREF_WORKERS_OPTIONS_PREFIX PREF_GCZEAL,
-                                        nullptr)) ||
 #endif
         NS_FAILED(Preferences::UnregisterCallback(
                                  LoadJSGCMemoryOptions,
@@ -2793,23 +2627,11 @@ RuntimeService::WorkerPrefChanged(const char* aPrefName, void* aClosure)
     static_cast<WorkerPreference>(reinterpret_cast<uintptr_t>(aClosure));
 
   switch (key) {
-    case WORKERPREF_DOM_CACHES:
-    case WORKERPREF_DOM_CACHES_TESTING:
-    case WORKERPREF_DOM_WORKERNOTIFICATION:
-    case WORKERPREF_DOM_SERVICEWORKERNOTIFICATION:
-    case WORKERPREF_PERFORMANCE_LOGGING_ENABLED:
-#ifdef DUMP_CONTROLLED_BY_PREF
-    case WORKERPREF_DUMP:
-#endif
-    case WORKERPREF_INTERCEPTION_ENABLED:
-    case WORKERPREF_INTERCEPTION_OPAQUE_ENABLED:
-    case WORKERPREF_OPEN_WINDOW_ENABLED:
-    case WORKERPREF_SERVICEWORKERS:
-    case WORKERPREF_SERVICEWORKERS_TESTING:
-    case WORKERPREF_PUSH:
-    case WORKERPREF_REQUESTCACHE:
-    case WORKERPREF_REQUESTCONTEXT:
-    case WORKERPREF_OFFSCREENCANVAS:
+#define WORKER_SIMPLE_PREF(name, getter, NAME) case WORKERPREF_##NAME:
+#define WORKER_PREF(name, callback)
+#include "WorkerPrefs.h"
+#undef WORKER_SIMPLE_PREF
+#undef WORKER_PREF
       sDefaultPreferences[key] = Preferences::GetBool(aPrefName, false);
       break;
 
@@ -2829,7 +2651,7 @@ RuntimeService::JSVersionChanged(const char* /* aPrefName */, void* /* aClosure
 {
   AssertIsOnMainThread();
 
-  bool useLatest = Preferences::GetBool(PREF_WORKERS_LATEST_JS_VERSION, false);
+  bool useLatest = Preferences::GetBool("dom.workers.latestJSVersion", false);
   JS::CompartmentOptions& options = sDefaultJSSettings.content.compartmentOptions;
   options.setVersion(useLatest ? JSVERSION_LATEST : JSVERSION_DEFAULT);
 }
diff --git a/dom/workers/ServiceWorkerClient.h b/dom/workers/ServiceWorkerClient.h
index 17c21ede878..e81eb37c541 100644
--- a/dom/workers/ServiceWorkerClient.h
+++ b/dom/workers/ServiceWorkerClient.h
@@ -57,6 +57,7 @@ public:
     , mId(aClientInfo.mClientId)
     , mUrl(aClientInfo.mUrl)
     , mWindowId(aClientInfo.mWindowId)
+    , mFrameType(aClientInfo.mFrameType)
   {
     MOZ_ASSERT(aOwner);
   }
@@ -78,6 +79,12 @@ public:
     aUrl.Assign(mUrl);
   }
 
+  mozilla::dom::FrameType
+  FrameType() const
+  {
+    return mFrameType;
+  }
+
   void
   PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
               const Optional<Sequence<JS::Value>>& aTransferable,
@@ -96,6 +103,7 @@ private:
 
 protected:
   uint64_t mWindowId;
+  mozilla::dom::FrameType mFrameType;
 };
 
 } // namespace workers
diff --git a/dom/workers/ServiceWorkerContainer.h b/dom/workers/ServiceWorkerContainer.h
index b96ac9c9914..c9f2fb8f50d 100644
--- a/dom/workers/ServiceWorkerContainer.h
+++ b/dom/workers/ServiceWorkerContainer.h
@@ -29,7 +29,6 @@ public:
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ServiceWorkerContainer, DOMEventTargetHelper)
 
   IMPL_EVENT_HANDLER(controllerchange)
-  IMPL_EVENT_HANDLER(reloadpage)
   IMPL_EVENT_HANDLER(error)
   IMPL_EVENT_HANDLER(message)
 
diff --git a/dom/workers/ServiceWorkerEvents.cpp b/dom/workers/ServiceWorkerEvents.cpp
index b90d38ecbe5..d7bdcb550f1 100644
--- a/dom/workers/ServiceWorkerEvents.cpp
+++ b/dom/workers/ServiceWorkerEvents.cpp
@@ -5,7 +5,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "ServiceWorkerEvents.h"
-#include "ServiceWorkerClient.h"
 
 #include "nsIHttpChannelInternal.h"
 #include "nsINetworkInterceptController.h"
@@ -60,7 +59,7 @@ CancelChannelRunnable::Run()
 }
 
 FetchEvent::FetchEvent(EventTarget* aOwner)
-: Event(aOwner, nullptr, nullptr)
+: ExtendableEvent(aOwner)
 , mIsReload(false)
 , mWaitToRespond(false)
 {
@@ -72,12 +71,10 @@ FetchEvent::~FetchEvent()
 
 void
 FetchEvent::PostInit(nsMainThreadPtrHandle<nsIInterceptedChannel>& aChannel,
-                     const nsACString& aScriptSpec,
-                     UniquePtr<ServiceWorkerClientInfo>&& aClientInfo)
+                     const nsACString& aScriptSpec)
 {
   mChannel = aChannel;
   mScriptSpec.Assign(aScriptSpec);
-  mClientInfo = Move(aClientInfo);
 }
 
 /*static*/ already_AddRefed<FetchEvent>
@@ -94,10 +91,7 @@ FetchEvent::Constructor(const GlobalObject& aGlobal,
   e->SetTrusted(trusted);
   e->mRequest = aOptions.mRequest.WasPassed() ?
       &aOptions.mRequest.Value() : nullptr;
-  e->mIsReload = aOptions.mIsReload.WasPassed() ?
-      aOptions.mIsReload.Value() : false;
-  e->mClient = aOptions.mClient.WasPassed() ?
-      &aOptions.mClient.Value() : nullptr;
+  e->mIsReload = aOptions.mIsReload;
   return e.forget();
 }
 
@@ -460,32 +454,14 @@ FetchEvent::RespondWith(Promise& aArg, ErrorResult& aRv)
   aArg.AppendNativeHandler(handler);
 }
 
-already_AddRefed<ServiceWorkerClient>
-FetchEvent::GetClient()
-{
-  if (!mClient) {
-    if (!mClientInfo) {
-      return nullptr;
-    }
-
-    WorkerPrivate* worker = GetCurrentThreadWorkerPrivate();
-    MOZ_ASSERT(worker);
-    RefPtr<nsIGlobalObject> global = worker->GlobalScope();
-
-    mClient = new ServiceWorkerClient(global, *mClientInfo);
-  }
-  RefPtr<ServiceWorkerClient> client = mClient;
-  return client.forget();
-}
-
-NS_IMPL_ADDREF_INHERITED(FetchEvent, Event)
-NS_IMPL_RELEASE_INHERITED(FetchEvent, Event)
+NS_IMPL_ADDREF_INHERITED(FetchEvent, ExtendableEvent)
+NS_IMPL_RELEASE_INHERITED(FetchEvent, ExtendableEvent)
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(FetchEvent)
-NS_INTERFACE_MAP_END_INHERITING(Event)
+NS_INTERFACE_MAP_END_INHERITING(ExtendableEvent)
 
-NS_IMPL_CYCLE_COLLECTION_INHERITED(FetchEvent, Event, mRequest, mClient,
-                                   mPromise)
+NS_IMPL_CYCLE_COLLECTION_INHERITED(FetchEvent, ExtendableEvent,
+                                   mRequest, mPromise)
 
 ExtendableEvent::ExtendableEvent(EventTarget* aOwner)
   : Event(aOwner, nullptr, nullptr)
diff --git a/dom/workers/ServiceWorkerEvents.h b/dom/workers/ServiceWorkerEvents.h
index 6c27d7816e9..1e095b8ff8a 100644
--- a/dom/workers/ServiceWorkerEvents.h
+++ b/dom/workers/ServiceWorkerEvents.h
@@ -35,8 +35,6 @@ class ResponseOrPromise;
 
 BEGIN_WORKERS_NAMESPACE
 
-class ServiceWorkerClient;
-
 class CancelChannelRunnable final : public nsRunnable
 {
   nsMainThreadPtrHandle<nsIInterceptedChannel> mChannel;
@@ -48,78 +46,6 @@ public:
   NS_IMETHOD Run() override;
 };
 
-class FetchEvent final : public Event
-{
-  nsMainThreadPtrHandle<nsIInterceptedChannel> mChannel;
-  RefPtr<ServiceWorkerClient> mClient;
-  RefPtr<Request> mRequest;
-  nsCString mScriptSpec;
-  UniquePtr<ServiceWorkerClientInfo> mClientInfo;
-  RefPtr<Promise> mPromise;
-  bool mIsReload;
-  bool mWaitToRespond;
-protected:
-  explicit FetchEvent(EventTarget* aOwner);
-  ~FetchEvent();
-
-public:
-  NS_DECL_ISUPPORTS_INHERITED
-  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(FetchEvent, Event)
-  NS_FORWARD_TO_EVENT
-
-  virtual JSObject* WrapObjectInternal(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override
-  {
-    return FetchEventBinding::Wrap(aCx, this, aGivenProto);
-  }
-
-  void PostInit(nsMainThreadPtrHandle<nsIInterceptedChannel>& aChannel,
-                const nsACString& aScriptSpec,
-                UniquePtr<ServiceWorkerClientInfo>&& aClientInfo);
-
-  static already_AddRefed<FetchEvent>
-  Constructor(const GlobalObject& aGlobal,
-              const nsAString& aType,
-              const FetchEventInit& aOptions,
-              ErrorResult& aRv);
-
-  bool
-  WaitToRespond() const
-  {
-    return mWaitToRespond;
-  }
-
-  Request*
-  Request_() const
-  {
-    return mRequest;
-  }
-
-  already_AddRefed<ServiceWorkerClient>
-  GetClient();
-
-  bool
-  IsReload() const
-  {
-    return mIsReload;
-  }
-
-  void
-  RespondWith(Promise& aArg, ErrorResult& aRv);
-
-  already_AddRefed<Promise>
-  GetPromise() const
-  {
-    RefPtr<Promise> p = mPromise;
-    return p.forget();
-  }
-
-  already_AddRefed<Promise>
-  ForwardTo(const nsAString& aUrl);
-
-  already_AddRefed<Promise>
-  Default();
-};
-
 class ExtendableEvent : public Event
 {
   nsTArray<RefPtr<Promise>> mPromises;
@@ -172,6 +98,72 @@ public:
   }
 };
 
+class FetchEvent final : public ExtendableEvent
+{
+  nsMainThreadPtrHandle<nsIInterceptedChannel> mChannel;
+  RefPtr<Request> mRequest;
+  nsCString mScriptSpec;
+  RefPtr<Promise> mPromise;
+  bool mIsReload;
+  bool mWaitToRespond;
+protected:
+  explicit FetchEvent(EventTarget* aOwner);
+  ~FetchEvent();
+
+public:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(FetchEvent, ExtendableEvent)
+  NS_FORWARD_TO_EVENT
+
+  virtual JSObject* WrapObjectInternal(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override
+  {
+    return FetchEventBinding::Wrap(aCx, this, aGivenProto);
+  }
+
+  void PostInit(nsMainThreadPtrHandle<nsIInterceptedChannel>& aChannel,
+                const nsACString& aScriptSpec);
+
+  static already_AddRefed<FetchEvent>
+  Constructor(const GlobalObject& aGlobal,
+              const nsAString& aType,
+              const FetchEventInit& aOptions,
+              ErrorResult& aRv);
+
+  bool
+  WaitToRespond() const
+  {
+    return mWaitToRespond;
+  }
+
+  Request*
+  GetRequest_() const
+  {
+    return mRequest;
+  }
+
+  bool
+  IsReload() const
+  {
+    return mIsReload;
+  }
+
+  void
+  RespondWith(Promise& aArg, ErrorResult& aRv);
+
+  already_AddRefed<Promise>
+  GetPromise() const
+  {
+    RefPtr<Promise> p = mPromise;
+    return p.forget();
+  }
+
+  already_AddRefed<Promise>
+  ForwardTo(const nsAString& aUrl);
+
+  already_AddRefed<Promise>
+  Default();
+};
+
 #ifndef MOZ_SIMPLEPUSH
 
 class PushMessageData final : public nsISupports,
diff --git a/dom/workers/ServiceWorkerPrivate.cpp b/dom/workers/ServiceWorkerPrivate.cpp
index 367310d3846..11504551fd1 100644
--- a/dom/workers/ServiceWorkerPrivate.cpp
+++ b/dom/workers/ServiceWorkerPrivate.cpp
@@ -915,7 +915,6 @@ class FetchEventRunnable : public ExtendableFunctionalEventWorkerRunnable
   const nsCString mScriptSpec;
   nsTArray<nsCString> mHeaderNames;
   nsTArray<nsCString> mHeaderValues;
-  UniquePtr<ServiceWorkerClientInfo> mClientInfo;
   nsCString mSpec;
   nsCString mMethod;
   bool mIsReload;
@@ -940,7 +939,6 @@ public:
         aWorkerPrivate, aKeepAliveToken, aRegistration)
     , mInterceptedChannel(aChannel)
     , mScriptSpec(aScriptSpec)
-    , mClientInfo(Move(aClientInfo))
     , mIsReload(aIsReload)
     , mIsHttpChannel(false)
     , mRequestMode(RequestMode::No_cors)
@@ -1153,7 +1151,7 @@ private:
     init.mRequest.Value() = request;
     init.mBubbles = false;
     init.mCancelable = true;
-    init.mIsReload.Construct(mIsReload);
+    init.mIsReload = mIsReload;
     RefPtr<FetchEvent> event =
       FetchEvent::Constructor(globalObj, NS_LITERAL_STRING("fetch"), init, result);
     if (NS_WARN_IF(result.Failed())) {
@@ -1161,7 +1159,7 @@ private:
       return false;
     }
 
-    event->PostInit(mInterceptedChannel, mScriptSpec, Move(mClientInfo));
+    event->PostInit(mInterceptedChannel, mScriptSpec);
     event->SetTrusted(true);
 
     RefPtr<EventTarget> target = do_QueryObject(aWorkerPrivate->GlobalScope());
diff --git a/dom/workers/ServiceWorkerWindowClient.h b/dom/workers/ServiceWorkerWindowClient.h
index 8ff7b1d7dc5..feb9fbf90d7 100644
--- a/dom/workers/ServiceWorkerWindowClient.h
+++ b/dom/workers/ServiceWorkerWindowClient.h
@@ -24,8 +24,7 @@ public:
                             const ServiceWorkerClientInfo& aClientInfo)
     : ServiceWorkerClient(aOwner, aClientInfo),
       mVisibilityState(aClientInfo.mVisibilityState),
-      mFocused(aClientInfo.mFocused),
-      mFrameType(aClientInfo.mFrameType)
+      mFocused(aClientInfo.mFocused)
   {
   }
 
@@ -44,12 +43,6 @@ public:
     return mFocused;
   }
 
-  mozilla::dom::FrameType
-  FrameType() const
-  {
-    return mFrameType;
-  }
-
   already_AddRefed<Promise>
   Focus(ErrorResult& aRv) const;
 
@@ -59,7 +52,6 @@ private:
 
   mozilla::dom::VisibilityState mVisibilityState;
   bool mFocused;
-  mozilla::dom::FrameType mFrameType;
 };
 
 } // namespace workers
diff --git a/dom/workers/WorkerPrefs.h b/dom/workers/WorkerPrefs.h
new file mode 100644
index 00000000000..358da36349b
--- /dev/null
+++ b/dom/workers/WorkerPrefs.h
@@ -0,0 +1,48 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// This is the list of the preferences that are exposed to workers.
+// The format is as follows:
+//
+//   WORKER_SIMPLE_PREF("foo.bar", FooBar, FOO_BAR, UpdaterFunction)
+//
+//   * First argument is the name of the pref.
+//   * The name of the getter function.  This defines a FindName()
+//     function that returns the value of the pref on WorkerPrivate.
+//   * The macro version of the name.  This defines a WORKERPREF_FOO_BAR
+//     macro in Workers.h.
+//   * The name of the function that updates the new value of a pref.
+//
+//   WORKER_PREF("foo.bar", UpdaterFunction)
+//
+//   * First argument is the name of the pref.
+//   * The name of the function that updates the new value of a pref.
+
+#if !(defined(DEBUG) || defined(MOZ_ENABLE_JS_DUMP))
+WORKER_SIMPLE_PREF("browser.dom.window.dump.enabled", DumpEnabled, DUMP)
+#endif
+WORKER_SIMPLE_PREF("dom.caches.enabled", DOMCachesEnabled, DOM_CACHES)
+WORKER_SIMPLE_PREF("dom.caches.testing.enabled", DOMCachesTestingEnabled, DOM_CACHES_TESTING)
+WORKER_SIMPLE_PREF("dom.performance.enable_user_timing_logging", PerformanceLoggingEnabled, PERFORMANCE_LOGGING_ENABLED)
+WORKER_SIMPLE_PREF("dom.webnotifications.enabled", DOMWorkerNotificationEnabled, DOM_WORKERNOTIFICATION)
+WORKER_SIMPLE_PREF("dom.webnotifications.serviceworker.enabled", DOMServiceWorkerNotificationEnabled, DOM_SERVICEWORKERNOTIFICATION)
+WORKER_SIMPLE_PREF("dom.serviceWorkers.enabled", ServiceWorkersEnabled, SERVICEWORKERS_ENABLED)
+WORKER_SIMPLE_PREF("dom.serviceWorkers.testing.enabled", ServiceWorkersTestingEnabled, SERVICEWORKERS_TESTING_ENABLED)
+WORKER_SIMPLE_PREF("dom.serviceWorkers.interception.enabled", InterceptionEnabled, INTERCEPTION_ENABLED)
+WORKER_SIMPLE_PREF("dom.serviceWorkers.interception.opaque.enabled", OpaqueInterceptionEnabled, INTERCEPTION_OPAQUE_ENABLED)
+WORKER_SIMPLE_PREF("dom.serviceWorkers.openWindow.enabled", OpenWindowEnabled, OPEN_WINDOW_ENABLED)
+WORKER_SIMPLE_PREF("dom.push.enabled", PushEnabled, PUSH_ENABLED)
+WORKER_SIMPLE_PREF("dom.requestcache.enabled", RequestCacheEnabled, REQUESTCACHE_ENABLED)
+WORKER_SIMPLE_PREF("dom.requestcontext.enabled", RequestContextEnabled, REQUESTCONTEXT_ENABLED)
+WORKER_SIMPLE_PREF("gfx.offscreencanvas.enabled", OffscreenCanvasEnabled, OFFSCREENCANVAS_ENABLED)
+WORKER_PREF("dom.workers.latestJSVersion", JSVersionChanged)
+WORKER_PREF("intl.accept_languages", PrefLanguagesChanged)
+WORKER_PREF("general.appname.override", AppNameOverrideChanged)
+WORKER_PREF("general.appversion.override", AppVersionOverrideChanged)
+WORKER_PREF("general.platform.override", PlatformOverrideChanged)
+#ifdef JS_GC_ZEAL
+WORKER_PREF("dom.workers.options.gcZeal", LoadGCZealOptions)
+#endif
diff --git a/dom/workers/WorkerPrivate.h b/dom/workers/WorkerPrivate.h
index 2064eba7bbe..7d5ab635054 100644
--- a/dom/workers/WorkerPrivate.h
+++ b/dom/workers/WorkerPrivate.h
@@ -1229,111 +1229,17 @@ public:
   bool
   RegisterBindings(JSContext* aCx, JS::Handle<JSObject*> aGlobal);
 
-  bool
-  DumpEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_DUMP];
-  }
-
-  bool
-  DOMCachesEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_DOM_CACHES];
-  }
-
-  bool
-  ServiceWorkersEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_SERVICEWORKERS];
-  }
-
-  // Determine if the SW testing browser-wide pref is set
-  bool
-  ServiceWorkersTestingEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_SERVICEWORKERS_TESTING];
-  }
-
-  bool
-  InterceptionEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_INTERCEPTION_ENABLED];
-  }
-
-  bool
-  OpenWindowEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_OPEN_WINDOW_ENABLED];
-  }
-
-  bool
-  OpaqueInterceptionEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_INTERCEPTION_OPAQUE_ENABLED];
-  }
-
-  bool
-  DOMWorkerNotificationEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_DOM_WORKERNOTIFICATION];
-  }
-
-  bool
-  DOMServiceWorkerNotificationEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_DOM_SERVICEWORKERNOTIFICATION];
-  }
-
-  bool
-  DOMCachesTestingEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_DOM_CACHES_TESTING];
-  }
-
-  bool
-  PerformanceLoggingEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_PERFORMANCE_LOGGING_ENABLED];
-  }
-
-  bool
-  PushEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_PUSH];
-  }
-
-  bool
-  RequestCacheEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_REQUESTCACHE];
-  }
-
-  bool
-  RequestContextEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_REQUESTCONTEXT];
-  }
-
-  bool
-  OffscreenCanvasEnabled() const
-  {
-    AssertIsOnWorkerThread();
-    return mPreferences[WORKERPREF_OFFSCREENCANVAS];
+#define WORKER_SIMPLE_PREF(name, getter, NAME)                                \
+  bool                                                                        \
+  getter() const                                                              \
+  {                                                                           \
+    AssertIsOnWorkerThread();                                                 \
+    return mPreferences[WORKERPREF_##NAME];                                   \
   }
+#define WORKER_PREF(name, callback)
+#include "WorkerPrefs.h"
+#undef WORKER_SIMPLE_PREF
+#undef WORKER_PREF
 
   bool
   OnLine() const
diff --git a/dom/workers/WorkerScope.cpp b/dom/workers/WorkerScope.cpp
index ff148f3b868..96256c542a3 100644
--- a/dom/workers/WorkerScope.cpp
+++ b/dom/workers/WorkerScope.cpp
@@ -318,9 +318,11 @@ WorkerGlobalScope::Dump(const Optional<nsAString>& aString) const
     return;
   }
 
+#if !(defined(DEBUG) || defined(MOZ_ENABLE_JS_DUMP))
   if (!mWorkerPrivate->DumpEnabled()) {
     return;
   }
+#endif
 
   NS_ConvertUTF16toUTF8 str(aString.Value());
 
diff --git a/dom/workers/WorkerScope.h b/dom/workers/WorkerScope.h
index ea3a86058c4..b4a6d1de94c 100644
--- a/dom/workers/WorkerScope.h
+++ b/dom/workers/WorkerScope.h
@@ -268,8 +268,6 @@ public:
   SkipWaiting(ErrorResult& aRv);
 
   IMPL_EVENT_HANDLER(activate)
-  IMPL_EVENT_HANDLER(beforeevicted)
-  IMPL_EVENT_HANDLER(evicted)
   IMPL_EVENT_HANDLER(fetch)
   IMPL_EVENT_HANDLER(install)
   IMPL_EVENT_HANDLER(message)
diff --git a/dom/workers/Workers.h b/dom/workers/Workers.h
index ab24080eb50..92f38429180 100644
--- a/dom/workers/Workers.h
+++ b/dom/workers/Workers.h
@@ -197,21 +197,11 @@ struct JSSettings
 
 enum WorkerPreference
 {
-  WORKERPREF_DUMP = 0, // browser.dom.window.dump.enabled
-  WORKERPREF_DOM_CACHES, // dom.caches.enabled
-  WORKERPREF_SERVICEWORKERS, // dom.serviceWorkers.enabled
-  WORKERPREF_INTERCEPTION_ENABLED, // dom.serviceWorkers.interception.enabled
-  WORKERPREF_OPEN_WINDOW_ENABLED, // dom.serviceWorkers.openWindow.enabled
-  WORKERPREF_DOM_WORKERNOTIFICATION, // dom.webnotifications.workers.enabled
-  WORKERPREF_DOM_SERVICEWORKERNOTIFICATION, // dom.webnotifications.serviceworker.enabled
-  WORKERPREF_DOM_CACHES_TESTING, // dom.caches.testing.enabled
-  WORKERPREF_SERVICEWORKERS_TESTING, // dom.serviceWorkers.testing.enabled
-  WORKERPREF_INTERCEPTION_OPAQUE_ENABLED, // dom.serviceWorkers.interception.opaque.enabled
-  WORKERPREF_PERFORMANCE_LOGGING_ENABLED, // dom.performance.enable_user_timing_logging
-  WORKERPREF_PUSH, // dom.push.enabled
-  WORKERPREF_REQUESTCACHE, // dom.requestcache.enabled
-  WORKERPREF_REQUESTCONTEXT, // dom.requestcontext.enabled
-  WORKERPREF_OFFSCREENCANVAS, // gfx.offscreencanvas.enabled
+#define WORKER_SIMPLE_PREF(name, getter, NAME) WORKERPREF_ ## NAME,
+#define WORKER_PREF(name, callback)
+#include "mozilla/dom/WorkerPrefs.h"
+#undef WORKER_SIMPLE_PREF
+#undef WORKER_PREF
   WORKERPREF_COUNT
 };
 
diff --git a/dom/workers/moz.build b/dom/workers/moz.build
index 6b0234cdd60..c8e2f2792e2 100644
--- a/dom/workers/moz.build
+++ b/dom/workers/moz.build
@@ -12,6 +12,7 @@ EXPORTS.mozilla.dom += [
     'ServiceWorkerMessageEvent.h',
     'ServiceWorkerRegistrar.h',
     'ServiceWorkerRegistration.h',
+    'WorkerPrefs.h',
     'WorkerPrivate.h',
     'WorkerRunnable.h',
     'WorkerScope.h',
diff --git a/dom/workers/test/serviceworkers/fetch/fetch_tests.js b/dom/workers/test/serviceworkers/fetch/fetch_tests.js
index d5958dff5d5..6e67699b5f3 100644
--- a/dom/workers/test/serviceworkers/fetch/fetch_tests.js
+++ b/dom/workers/test/serviceworkers/fetch/fetch_tests.js
@@ -375,3 +375,27 @@ fetch(new Request('empty-header', {headers:{"emptyheader":""}}))
   my_ok(false, "A promise was rejected with " + err);
   finish();
 });
+
+expectAsyncResult();
+fetch('fetchevent-extendable')
+.then(function(res) {
+  return res.text();
+}).then(function(body) {
+  my_ok(body == "extendable", "FetchEvent inherits from ExtendableEvent");
+  finish();
+}, function(err) {
+  my_ok(false, "A promise was rejected with " + err);
+  finish();
+});
+
+expectAsyncResult();
+fetch('fetchevent-request')
+.then(function(res) {
+  return res.text();
+}).then(function(body) {
+  my_ok(body == "nullable", "FetchEvent.request must be nullable");
+  finish();
+}, function(err) {
+  my_ok(false, "A promise was rejected with " + err);
+  finish();
+});
diff --git a/dom/workers/test/serviceworkers/fetch/plugin/worker.js b/dom/workers/test/serviceworkers/fetch/plugin/worker.js
index eaf7c4346b4..e97d062050d 100644
--- a/dom/workers/test/serviceworkers/fetch/plugin/worker.js
+++ b/dom/workers/test/serviceworkers/fetch/plugin/worker.js
@@ -1,7 +1,14 @@
 self.addEventListener("fetch", function(event) {
   var resource = event.request.url.split('/').pop();
-  if (event.client) {
-    event.client.postMessage({context: event.request.context,
-                              resource: resource});
-  }
+  event.waitUntil(
+    clients.matchAll()
+           .then(clients => {
+             clients.forEach(client => {
+               if (client.url.includes("plugins.html")) {
+                 client.postMessage({context: event.request.context,
+                                     resource: resource});
+               }
+             });
+           })
+  );
 });
diff --git a/dom/workers/test/serviceworkers/fetch_event_client.js b/dom/workers/test/serviceworkers/fetch_event_client.js
deleted file mode 100644
index 0296f12ef59..00000000000
--- a/dom/workers/test/serviceworkers/fetch_event_client.js
+++ /dev/null
@@ -1,6 +0,0 @@
-var CLIENT_URL =
-  "http://mochi.test:8888/tests/dom/workers/test/serviceworkers/sw_clients/dummy.html"
-
-self.addEventListener("fetch", function(event) {
-  event.client.postMessage({status: event.client.url === CLIENT_URL});
-});
diff --git a/dom/workers/test/serviceworkers/fetch_event_worker.js b/dom/workers/test/serviceworkers/fetch_event_worker.js
index 5c13b620654..6ff8f02b114 100644
--- a/dom/workers/test/serviceworkers/fetch_event_worker.js
+++ b/dom/workers/test/serviceworkers/fetch_event_worker.js
@@ -283,4 +283,20 @@ onfetch = function(ev) {
     }
     ev.respondWith(new Response("emptyheader"));
   }
+
+  else if (ev.request.url.includes('fetchevent-extendable')) {
+    if (ev instanceof ExtendableEvent) {
+      ev.respondWith(new Response("extendable"));
+    } else {
+      ev.respondWith(Promise.reject());
+    }
+  }
+
+  else if (ev.request.url.includes('fetchevent-request')) {
+    if ((new FetchEvent("foo")).request === null) {
+      ev.respondWith(new Response("nullable"));
+    } else {
+      ev.respondWith(Promise.reject());
+    }
+  }
 };
diff --git a/dom/workers/test/serviceworkers/mochitest.ini b/dom/workers/test/serviceworkers/mochitest.ini
index b3a85aec66b..7a6d6a1a38c 100644
--- a/dom/workers/test/serviceworkers/mochitest.ini
+++ b/dom/workers/test/serviceworkers/mochitest.ini
@@ -173,8 +173,6 @@ support-files =
   opaque_intercept_worker.js
   notify_loaded.js
   test_request_context.js
-  fetch_event_client.js
-  sw_clients/dummy.html
   fetch/plugin/worker.js
   fetch/plugin/plugins.html
   eventsource/*
@@ -271,7 +269,6 @@ skip-if = toolkit == "android" || toolkit == "gonk"
 [test_workerUpdate.html]
 [test_workerupdatefoundevent.html]
 [test_opaque_intercept.html]
-[test_fetch_event_client_postmessage.html]
 [test_xslt.html]
 [test_escapedSlashes.html]
 [test_eventsource_intercept.html]
diff --git a/dom/workers/test/serviceworkers/sw_clients/dummy.html b/dom/workers/test/serviceworkers/sw_clients/dummy.html
deleted file mode 100644
index bfdb5f83187..00000000000
--- a/dom/workers/test/serviceworkers/sw_clients/dummy.html
+++ /dev/null
@@ -1,19 +0,0 @@
-<!--
-  Any copyright is dedicated to the Public Domain.
-  http://creativecommons.org/publicdomain/zero/1.0/
--->
-<!DOCTYPE HTML>
-<html>
-<head>
-  <title>Bug 1158735 - Dummy page</title>
-</head>
-<body>
-  <script type="text/javascript" >
-    window.onload = function() {
-      navigator.serviceWorker.ready.then(function(swr) {
-        fetch("foo.txt");
-      });
-    }
-  </script>
-</body>
-</html>
diff --git a/dom/workers/test/serviceworkers/test_fetch_event_client_postmessage.html b/dom/workers/test/serviceworkers/test_fetch_event_client_postmessage.html
deleted file mode 100644
index 07b9e43fdac..00000000000
--- a/dom/workers/test/serviceworkers/test_fetch_event_client_postmessage.html
+++ /dev/null
@@ -1,73 +0,0 @@
-<!--
-  Any copyright is dedicated to the Public Domain.
-  http://creativecommons.org/publicdomain/zero/1.0/
--->
-<!DOCTYPE HTML>
-<html>
-<head>
-  <title>Bug 1158735 - FetchEvent.client asserting in onFetch when there's no document.</title>
-  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
-</head>
-<body>
-  <p id="display"></p>
-  <div id="content" style="display: none"></div>
-  <pre id="test"></pre>
-  <script class="testbody" type="text/javascript">
-    SimpleTest.requestCompleteLog();
-
-    var registration;
-    function start() {
-      return navigator.serviceWorker.register("fetch_event_client.js", { scope: "./"})
-        .then((swr) => registration = swr);
-    }
-
-    function unregister() {
-      return registration.unregister().then(function(result) {
-        ok(result, "Unregister should return true.");
-      }, function(e) {
-        dump("Unregistering the SW failed with " + e + "\n");
-      });
-    }
-
-    function testFetchEvent() {
-      var p = new Promise(function(resolve, reject) {
-        var content = document.getElementById("content");
-        ok(content, "parent exists.");
-
-        var iframe = document.createElement('iframe');
-        iframe.setAttribute('src', "sw_clients/dummy.html");
-        content.appendChild(iframe);
-
-        var w = iframe.contentWindow;
-        w.navigator.serviceWorker.onmessage = function(msg) {
-          ok(msg.data.status, "Receive message posted by client successfully");
-
-          resolve();
-        }
-      });
-
-      return p;
-    }
-
-    function runTest() {
-      start()
-        .then(testFetchEvent)
-        .then(unregister)
-        .then(function() {
-        }).catch(function(e) {
-          ok(false, "Some test failed with error " + e);
-        }).then(SimpleTest.finish);
-    }
-
-    SimpleTest.waitForExplicitFinish();
-    SpecialPowers.pushPrefEnv({"set": [
-      ["dom.serviceWorkers.exemptFromPerDomainMax", true],
-      ["dom.serviceWorkers.enabled", true],
-      ["dom.serviceWorkers.testing.enabled", true],
-      ["dom.serviceWorkers.testing.enabled", true],
-      ['dom.serviceWorkers.interception.enabled', true],
-    ]}, runTest);
-  </script>
-</body>
-</html>
diff --git a/dom/workers/test/serviceworkers/unresolved_fetch_worker.js b/dom/workers/test/serviceworkers/unresolved_fetch_worker.js
index 8ce9d549c51..993ff2fc258 100644
--- a/dom/workers/test/serviceworkers/unresolved_fetch_worker.js
+++ b/dom/workers/test/serviceworkers/unresolved_fetch_worker.js
@@ -1,9 +1,12 @@
 onfetch = function(event) {
-  if (!event.client) {
-    dump("ERROR: event doesnt have a client");
-  }
-
-  event.client.postMessage("continue");
+  event.waitUntil(
+    clients.matchAll()
+           .then(clients => {
+             clients.forEach(client => {
+               client.postMessage("continue");
+             });
+           })
+  );
 
   // never resolve
   event.respondWith(new Promise(function(res, rej) {}));
diff --git a/dom/xbl/nsXBLPrototypeHandler.cpp b/dom/xbl/nsXBLPrototypeHandler.cpp
index 2e4746001f9..153f60003b6 100644
--- a/dom/xbl/nsXBLPrototypeHandler.cpp
+++ b/dom/xbl/nsXBLPrototypeHandler.cpp
@@ -572,9 +572,10 @@ nsXBLPrototypeHandler::GetController(EventTarget* aTarget)
   }
 
   if (!controllers) {
-    nsCOMPtr<nsIDOMWindow> domWindow(do_QueryInterface(aTarget));
-    if (domWindow)
+    nsCOMPtr<nsPIDOMWindow> domWindow(do_QueryInterface(aTarget));
+    if (domWindow) {
       domWindow->GetControllers(getter_AddRefs(controllers));
+    }
   }
 
   // Return the first controller.
diff --git a/dom/xml/nsXMLPrettyPrinter.cpp b/dom/xml/nsXMLPrettyPrinter.cpp
index 9f0f8c5e12d..2feb3cc0e5f 100644
--- a/dom/xml/nsXMLPrettyPrinter.cpp
+++ b/dom/xml/nsXMLPrettyPrinter.cpp
@@ -5,14 +5,13 @@
  
 #include "nsXMLPrettyPrinter.h"
 #include "nsContentUtils.h"
-#include "nsIDOMCSSStyleDeclaration.h"
+#include "nsICSSDeclaration.h"
 #include "nsIDOMDocumentXBL.h"
 #include "nsIObserver.h"
 #include "nsIXSLTProcessor.h"
 #include "nsSyncLoadService.h"
 #include "nsPIDOMWindow.h"
 #include "nsIDOMElement.h"
-#include "nsIDOMDocument.h"
 #include "nsIServiceManager.h"
 #include "nsNetUtil.h"
 #include "mozilla/dom/Element.h"
@@ -55,22 +54,24 @@ nsXMLPrettyPrinter::PrettyPrint(nsIDocument* aDocument,
 
     // check if we're in an invisible iframe
     nsPIDOMWindow *internalWin = aDocument->GetWindow();
-    nsCOMPtr<nsIDOMElement> frameElem;
+    nsCOMPtr<Element> frameElem;
     if (internalWin) {
-        internalWin->GetFrameElement(getter_AddRefs(frameElem));
+        frameElem = internalWin->GetFrameElementInternal();
     }
 
     if (frameElem) {
-        nsCOMPtr<nsIDOMCSSStyleDeclaration> computedStyle;
-        nsCOMPtr<nsIDOMDocument> frameOwnerDoc;
-        frameElem->GetOwnerDocument(getter_AddRefs(frameOwnerDoc));
-        if (frameOwnerDoc) {
-            nsCOMPtr<nsIDOMWindow> window;
-            frameOwnerDoc->GetDefaultView(getter_AddRefs(window));
-            if (window) {
-                window->GetComputedStyle(frameElem,
-                                         EmptyString(),
-                                         getter_AddRefs(computedStyle));
+        nsCOMPtr<nsICSSDeclaration> computedStyle;
+        if (nsIDocument* frameOwnerDoc = frameElem->OwnerDoc()) {
+            nsCOMPtr<nsIDOMWindow> window = frameOwnerDoc->GetDefaultView();
+            nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(window);
+            if (piWindow) {
+                piWindow = piWindow->GetCurrentInnerWindow();
+
+                ErrorResult dummy;
+                computedStyle = piWindow->GetComputedStyle(*frameElem,
+                                                           EmptyString(),
+                                                           dummy);
+                dummy.SuppressException();
             }
         }
 
diff --git a/dom/xul/nsXULCommandDispatcher.cpp b/dom/xul/nsXULCommandDispatcher.cpp
index 1d0826503b9..e317b15b327 100644
--- a/dom/xul/nsXULCommandDispatcher.cpp
+++ b/dom/xul/nsXULCommandDispatcher.cpp
@@ -160,13 +160,11 @@ nsXULCommandDispatcher::GetFocusedWindow(nsIDOMWindow** aWindow)
 
   // Make sure the caller can access this window. The caller can access this
   // window iff it can access the document.
-  nsCOMPtr<nsIDOMDocument> domdoc;
-  nsresult rv = window->GetDocument(getter_AddRefs(domdoc));
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsIDocument> doc = window->GetDoc();
 
   // Note: If there is no document, then this window has been cleared and
   // there's nothing left to protect, so let the window pass through.
-  if (domdoc && !nsContentUtils::CanCallerAccess(domdoc))
+  if (doc && !nsContentUtils::CanCallerAccess(doc))
     return NS_ERROR_DOM_SECURITY_ERR;
 
   window.forget(aWindow);
diff --git a/dom/xul/nsXULPopupListener.cpp b/dom/xul/nsXULPopupListener.cpp
index 829547fc7a1..bfa5bf09f71 100644
--- a/dom/xul/nsXULPopupListener.cpp
+++ b/dom/xul/nsXULPopupListener.cpp
@@ -120,15 +120,13 @@ nsXULPopupListener::HandleEvent(nsIDOMEvent* aEvent)
 
   if (!targetNode && mIsContext) {
     // Not a DOM node, see if it's the DOM window (bug 380818).
-    nsCOMPtr<nsIDOMWindow> domWin = do_QueryInterface(target);
+    nsCOMPtr<nsPIDOMWindow> domWin = do_QueryInterface(target);
     if (!domWin) {
       return NS_ERROR_DOM_WRONG_TYPE_ERR;
     }
     // Try to use the root node as target node.
-    nsCOMPtr<nsIDOMDocument> domDoc;
-    domWin->GetDocument(getter_AddRefs(domDoc));
+    nsCOMPtr<nsIDocument> doc = domWin->GetDoc();
 
-    nsCOMPtr<nsIDocument> doc = do_QueryInterface(domDoc);
     if (doc)
       targetNode = do_QueryInterface(doc->GetRootElement());
     if (!targetNode) {
diff --git a/editor/composer/nsComposerCommandsUpdater.cpp b/editor/composer/nsComposerCommandsUpdater.cpp
index 161584101d7..ff582271e00 100644
--- a/editor/composer/nsComposerCommandsUpdater.cpp
+++ b/editor/composer/nsComposerCommandsUpdater.cpp
@@ -339,11 +339,13 @@ nsComposerCommandsUpdater::UpdateOneCommand(const char *aCommand)
 bool
 nsComposerCommandsUpdater::SelectionIsCollapsed()
 {
-  nsCOMPtr<nsIDOMWindow> domWindow = do_QueryReferent(mDOMWindow);
+  nsCOMPtr<nsPIDOMWindow> domWindow = do_QueryReferent(mDOMWindow);
   NS_ENSURE_TRUE(domWindow, true);
 
-  nsCOMPtr<nsISelection> domSelection;
-  if (NS_SUCCEEDED(domWindow->GetSelection(getter_AddRefs(domSelection))) && domSelection)
+  domWindow = domWindow->GetOuterWindow();
+  NS_ENSURE_TRUE(domWindow, true);
+
+  if (nsCOMPtr<nsISelection> domSelection = domWindow->GetSelection())
   {
     bool selectionCollapsed = false;
     domSelection->GetIsCollapsed(&selectionCollapsed);
diff --git a/editor/composer/nsEditingSession.cpp b/editor/composer/nsEditingSession.cpp
index aa8c1928267..73b3b806c39 100644
--- a/editor/composer/nsEditingSession.cpp
+++ b/editor/composer/nsEditingSession.cpp
@@ -302,11 +302,12 @@ nsEditingSession::SetupEditorOnWindow(nsIDOMWindow *aWindow)
   //must get the content type
   // Note: the doc gets this from the network channel during StartPageLoad,
   //    so we don't have to get it from there ourselves
-  nsCOMPtr<nsIDOMDocument> doc;
   nsAutoCString mimeCType;
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aWindow);
+  MOZ_ASSERT(window);
 
   //then lets check the mime type
-  if (NS_SUCCEEDED(aWindow->GetDocument(getter_AddRefs(doc))) && doc)
+  if (nsCOMPtr<nsIDocument> doc = window->GetDoc())
   {
     nsAutoString mimeType;
     if (NS_SUCCEEDED(doc->GetContentType(mimeType)))
@@ -534,9 +535,11 @@ nsEditingSession::TearDownEditorOnWindow(nsIDOMWindow *aWindow)
   mDoneSetup = false;
 
   // Check if we're turning off editing (from contentEditable or designMode).
-  nsCOMPtr<nsIDOMDocument> domDoc;
-  aWindow->GetDocument(getter_AddRefs(domDoc));
-  nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(domDoc);
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aWindow);
+  MOZ_ASSERT(window);
+
+  nsCOMPtr<nsIDocument> doc = window->GetDoc();
+  nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(doc);
   bool stopEditing = htmlDoc && htmlDoc->IsEditingOn();
   if (stopEditing)
     RemoveWebProgressListener(aWindow);
@@ -572,9 +575,6 @@ nsEditingSession::TearDownEditorOnWindow(nsIDOMWindow *aWindow)
 
     if (mMakeWholeDocumentEditable)
     {
-      nsCOMPtr<nsIDocument> doc = do_QueryInterface(domDoc, &rv);
-      NS_ENSURE_SUCCESS(rv, rv);
-
       doc->SetEditableFlag(false);
       nsCOMPtr<nsIHTMLDocument> htmlDocument = do_QueryInterface(doc);
       if (htmlDocument) {
@@ -673,8 +673,8 @@ nsEditingSession::OnStateChange(nsIWebProgress *aWebProgress,
         nsCOMPtr<nsIDOMWindow> window;
         aWebProgress->GetDOMWindow(getter_AddRefs(window));
 
-        nsCOMPtr<nsIDOMDocument> doc;
-        window->GetDocument(getter_AddRefs(doc));
+        nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(window);
+        nsCOMPtr<nsIDocument> doc = piWindow->GetDoc();
 
         nsCOMPtr<nsIHTMLDocument> htmlDoc(do_QueryInterface(doc));
 
@@ -800,11 +800,10 @@ nsEditingSession::OnLocationChange(nsIWebProgress *aWebProgress,
   nsresult rv = aWebProgress->GetDOMWindow(getter_AddRefs(domWindow));
   NS_ENSURE_SUCCESS(rv, rv);
 
-  nsCOMPtr<nsIDOMDocument> domDoc;
-  rv = domWindow->GetDocument(getter_AddRefs(domDoc));
-  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(domWindow);
+  MOZ_ASSERT(piWindow);
 
-  nsCOMPtr<nsIDocument> doc = do_QueryInterface(domDoc);
+  nsCOMPtr<nsIDocument> doc = piWindow->GetDoc();
   NS_ENSURE_TRUE(doc, NS_ERROR_FAILURE);
 
   doc->SetDocumentURI(aURI);
@@ -1162,8 +1161,11 @@ nsEditingSession::SetupEditorCommandController(
   NS_ENSURE_ARG_POINTER(aContext);
   NS_ENSURE_ARG_POINTER(aControllerId);
 
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(aWindow);
+  MOZ_ASSERT(piWindow);
+
   nsCOMPtr<nsIControllers> controllers;
-  nsresult rv = aWindow->GetControllers(getter_AddRefs(controllers));
+  nsresult rv = piWindow->GetControllers(getter_AddRefs(controllers));
   NS_ENSURE_SUCCESS(rv, rv);
 
   // We only have to create each singleton controller once
@@ -1201,8 +1203,11 @@ nsEditingSession::SetEditorOnControllers(nsIDOMWindow *aWindow,
 {
   NS_ENSURE_TRUE(aWindow, NS_ERROR_NULL_POINTER);
 
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(aWindow);
+  MOZ_ASSERT(piWindow);
+
   nsCOMPtr<nsIControllers> controllers;
-  nsresult rv = aWindow->GetControllers(getter_AddRefs(controllers));
+  nsresult rv = piWindow->GetControllers(getter_AddRefs(controllers));
   NS_ENSURE_SUCCESS(rv, rv);
 
   nsCOMPtr<nsISupports> editorAsISupports = do_QueryInterface(aEditor);
@@ -1253,8 +1258,9 @@ nsEditingSession::RemoveEditorControllers(nsIDOMWindow *aWindow)
   // tearing down/detaching editor.
 
   nsCOMPtr<nsIControllers> controllers;
-  if (aWindow)
-    aWindow->GetControllers(getter_AddRefs(controllers));
+  if (nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(aWindow)) {
+    piWindow->GetControllers(getter_AddRefs(controllers));
+  }
 
   if (controllers)
   {
diff --git a/embedding/browser/moz.build b/embedding/browser/moz.build
index 6baf58591aa..8810fa7cd96 100644
--- a/embedding/browser/moz.build
+++ b/embedding/browser/moz.build
@@ -50,4 +50,5 @@ FINAL_LIBRARY = 'xul'
 LOCAL_INCLUDES += [
     '/dom/base',
     '/dom/svg',
+    '/layout/style',
 ]
diff --git a/embedding/browser/nsContextMenuInfo.cpp b/embedding/browser/nsContextMenuInfo.cpp
index 9413056b83d..25ff68c71c1 100644
--- a/embedding/browser/nsContextMenuInfo.cpp
+++ b/embedding/browser/nsContextMenuInfo.cpp
@@ -17,7 +17,7 @@
 #include "nsIDOMHTMLAreaElement.h"
 #include "nsIDOMHTMLLinkElement.h"
 #include "nsIDOMWindow.h"
-#include "nsIDOMCSSStyleDeclaration.h"
+#include "nsICSSDeclaration.h"
 #include "nsIDOMCSSValue.h"
 #include "nsIDOMCSSPrimitiveValue.h"
 #include "nsNetUtil.h"
@@ -29,6 +29,9 @@
 #include "nsAutoPtr.h"
 #include "imgRequestProxy.h"
 
+using mozilla::dom::Element;
+using mozilla::ErrorResult;
+
 NS_IMPL_ISUPPORTS(nsContextMenuInfo, nsIContextMenuInfo)
 
 nsContextMenuInfo::nsContextMenuInfo()
@@ -260,6 +263,11 @@ nsContextMenuInfo::GetBackgroundImageRequestInternal(nsIDOMNode* aDOMNode,
   document->GetDefaultView(getter_AddRefs(window));
   NS_ENSURE_TRUE(window, NS_ERROR_FAILURE);
 
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(window);
+  MOZ_ASSERT(piWindow);
+  piWindow = piWindow->GetCurrentInnerWindow();
+  MOZ_ASSERT(piWindow);
+
   nsCOMPtr<nsIDOMCSSPrimitiveValue> primitiveValue;
   nsAutoString bgStringValue;
 
@@ -267,15 +275,16 @@ nsContextMenuInfo::GetBackgroundImageRequestInternal(nsIDOMNode* aDOMNode,
   nsCOMPtr<nsIPrincipal> principal = doc ? doc->NodePrincipal() : nullptr;
 
   while (true) {
-    nsCOMPtr<nsIDOMElement> domElement(do_QueryInterface(domNode));
+    nsCOMPtr<Element> domElement(do_QueryInterface(domNode));
     // bail for the parent node of the root element or null argument
     if (!domElement) {
       break;
     }
 
-    nsCOMPtr<nsIDOMCSSStyleDeclaration> computedStyle;
-    window->GetComputedStyle(domElement, EmptyString(),
-                             getter_AddRefs(computedStyle));
+    ErrorResult dummy;
+    nsCOMPtr<nsICSSDeclaration> computedStyle =
+      piWindow->GetComputedStyle(*domElement, EmptyString(), dummy);
+    dummy.SuppressException();
     if (computedStyle) {
       nsCOMPtr<nsIDOMCSSValue> cssValue;
       computedStyle->GetPropertyCSSValue(NS_LITERAL_STRING("background-image"),
diff --git a/embedding/components/commandhandler/nsCommandManager.cpp b/embedding/components/commandhandler/nsCommandManager.cpp
index 7ac34534cc4..6e0274d7f40 100644
--- a/embedding/components/commandhandler/nsCommandManager.cpp
+++ b/embedding/components/commandhandler/nsCommandManager.cpp
@@ -248,10 +248,10 @@ nsCommandManager::GetControllerForCommand(const char* aCommand,
     }
   }
 
-  if (aTargetWindow) {
+  if (nsCOMPtr<nsPIDOMWindow> targetWindow = do_QueryInterface(aTargetWindow)) {
     // get the controller for this particular window
     nsCOMPtr<nsIControllers> controllers;
-    rv = aTargetWindow->GetControllers(getter_AddRefs(controllers));
+    rv = targetWindow->GetControllers(getter_AddRefs(controllers));
     if (NS_FAILED(rv)) {
       return rv;
     }
diff --git a/embedding/components/find/nsWebBrowserFind.cpp b/embedding/components/find/nsWebBrowserFind.cpp
index 2a6c13cd493..6bee42149af 100644
--- a/embedding/components/find/nsWebBrowserFind.cpp
+++ b/embedding/components/find/nsWebBrowserFind.cpp
@@ -354,13 +354,12 @@ void
 nsWebBrowserFind::SetSelectionAndScroll(nsIDOMWindow* aWindow,
                                         nsIDOMRange* aRange)
 {
-  nsCOMPtr<nsIDOMDocument> domDoc;
-  aWindow->GetDocument(getter_AddRefs(domDoc));
-  if (!domDoc) {
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(aWindow);
+  nsCOMPtr<nsIDocument> doc = piWindow->GetDoc();
+  if (!doc) {
     return;
   }
 
-  nsCOMPtr<nsIDocument> doc(do_QueryInterface(domDoc));
   nsIPresShell* presShell = doc->GetShell();
   if (!presShell) {
     return;
@@ -701,18 +700,13 @@ nsWebBrowserFind::SearchInFrame(nsIDOMWindow* aWindow, bool aWrapping,
 
   *aDidFind = false;
 
-  nsCOMPtr<nsIDOMDocument> domDoc;
-  nsresult rv = aWindow->GetDocument(getter_AddRefs(domDoc));
-  NS_ENSURE_SUCCESS(rv, rv);
-  if (!domDoc) {
-    return NS_ERROR_FAILURE;
-  }
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(aWindow);
 
   // Do security check, to ensure that the frame we're searching is
   // acccessible from the frame where the Find is being run.
 
   // get a uri for the window
-  nsCOMPtr<nsIDocument> theDoc = do_QueryInterface(domDoc);
+  nsCOMPtr<nsIDocument> theDoc = piWindow->GetDoc();
   if (!theDoc) {
     return NS_ERROR_FAILURE;
   }
@@ -721,6 +715,7 @@ nsWebBrowserFind::SearchInFrame(nsIDOMWindow* aWindow, bool aWrapping,
     return NS_ERROR_DOM_PROP_ACCESS_DENIED;
   }
 
+  nsresult rv;
   nsCOMPtr<nsIFind> find = do_CreateInstance(NS_FIND_CONTRACTID, &rv);
   NS_ENSURE_SUCCESS(rv, rv);
 
@@ -747,6 +742,9 @@ nsWebBrowserFind::SearchInFrame(nsIDOMWindow* aWindow, bool aWrapping,
 
   nsCOMPtr<nsIDOMRange> foundRange;
 
+  nsCOMPtr<nsIDOMDocument> domDoc = do_QueryInterface(theDoc);
+  MOZ_ASSERT(domDoc);
+
   // If !aWrapping, search from selection to end
   if (!aWrapping)
     rv = GetSearchLimits(searchRange, startPt, endPt, domDoc, sel, false);
@@ -794,13 +792,12 @@ nsWebBrowserFind::GetFrameSelection(nsIDOMWindow* aWindow, nsISelection** aSel)
 {
   *aSel = nullptr;
 
-  nsCOMPtr<nsIDOMDocument> domDoc;
-  aWindow->GetDocument(getter_AddRefs(domDoc));
-  if (!domDoc) {
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(aWindow);
+  nsCOMPtr<nsIDocument> doc = piWindow->GetDoc();
+  if (!doc) {
     return;
   }
 
-  nsCOMPtr<nsIDocument> doc(do_QueryInterface(domDoc));
   nsIPresShell* presShell = doc->GetShell();
   if (!presShell) {
     return;
diff --git a/embedding/components/printingui/mac/nsPrintProgress.cpp b/embedding/components/printingui/mac/nsPrintProgress.cpp
index e5d6325aa3b..f6c7f87e8ce 100644
--- a/embedding/components/printingui/mac/nsPrintProgress.cpp
+++ b/embedding/components/printingui/mac/nsPrintProgress.cpp
@@ -10,6 +10,7 @@
 #include "nsXPCOM.h"
 #include "nsISupportsPrimitives.h"
 #include "nsIComponentManager.h"
+#include "nsPIDOMWindow.h"
 
 NS_IMPL_ADDREF(nsPrintProgress)
 NS_IMPL_RELEASE(nsPrintProgress)
@@ -62,8 +63,11 @@ NS_IMETHODIMP nsPrintProgress::GetPrompter(nsIPrompt **_retval)
   NS_ENSURE_ARG_POINTER(_retval);
   *_retval = nullptr;
 
-  if (! m_closeProgress && m_dialog)
-    return m_dialog->GetPrompter(_retval);
+  if (! m_closeProgress && m_dialog) {
+    nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(m_dialog);
+    MOZ_ASSERT(window);
+    return window->GetPrompter(_retval);
+  }
     
   return NS_ERROR_FAILURE;
 }
diff --git a/embedding/components/printingui/unixshared/nsPrintProgress.cpp b/embedding/components/printingui/unixshared/nsPrintProgress.cpp
index c206720b5cf..99029bd87a7 100644
--- a/embedding/components/printingui/unixshared/nsPrintProgress.cpp
+++ b/embedding/components/printingui/unixshared/nsPrintProgress.cpp
@@ -92,13 +92,16 @@ NS_IMETHODIMP nsPrintProgress::OpenProgressDialog(nsIDOMWindow *parent,
     nsCOMPtr<nsIDOMWindow> ownerWindow = do_GetInterface(ownerXULWindow);
     NS_ENSURE_STATE(ownerWindow);
 
+    nsCOMPtr<nsPIDOMWindow> piOwnerWindow = do_QueryInterface(ownerWindow);
+    MOZ_ASSERT(piOwnerWindow);
+
     // Open the dialog.
     nsCOMPtr<nsIDOMWindow> newWindow;
 
-    rv = ownerWindow->OpenDialog(NS_ConvertASCIItoUTF16(dialogURL),
-                                 NS_LITERAL_STRING("_blank"),
-                                 NS_LITERAL_STRING("chrome,titlebar,dependent,centerscreen"),
-                                 array, getter_AddRefs(newWindow));
+    rv = piOwnerWindow->OpenDialog(NS_ConvertASCIItoUTF16(dialogURL),
+                                   NS_LITERAL_STRING("_blank"),
+                                   NS_LITERAL_STRING("chrome,titlebar,dependent,centerscreen"),
+                                   array, getter_AddRefs(newWindow));
   }
 
   return rv;
@@ -117,8 +120,11 @@ NS_IMETHODIMP nsPrintProgress::GetPrompter(nsIPrompt **_retval)
   NS_ENSURE_ARG_POINTER(_retval);
   *_retval = nullptr;
 
-  if (! m_closeProgress && m_dialog)
-    return m_dialog->GetPrompter(_retval);
+  if (! m_closeProgress && m_dialog) {
+    nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(m_dialog);
+    MOZ_ASSERT(window);
+    return window->GetPrompter(_retval);
+  }
     
   return NS_ERROR_FAILURE;
 }
diff --git a/embedding/components/printingui/win/nsPrintProgress.cpp b/embedding/components/printingui/win/nsPrintProgress.cpp
index 62dc0ca0446..154d2e39db6 100644
--- a/embedding/components/printingui/win/nsPrintProgress.cpp
+++ b/embedding/components/printingui/win/nsPrintProgress.cpp
@@ -120,12 +120,15 @@ NS_IMETHODIMP nsPrintProgress::OpenProgressDialog(nsIDOMWindow *parent,
     nsCOMPtr<nsIDOMWindow> ownerWindow = do_GetInterface(ownerXULWindow);
     NS_ENSURE_STATE(ownerWindow);
 
+    nsCOMPtr<nsPIDOMWindow> piOwnerWindow = do_QueryInterface(ownerWindow);
+    MOZ_ASSERT(piOwnerWindow);
+
     // Open the dialog.
     nsCOMPtr<nsIDOMWindow> newWindow;
-    rv = ownerWindow->OpenDialog(NS_ConvertASCIItoUTF16(dialogURL),
-                                 NS_LITERAL_STRING("_blank"),
-                                 NS_LITERAL_STRING("chrome,titlebar,dependent,centerscreen"),
-                                 array, getter_AddRefs(newWindow));
+    rv = piOwnerWindow->OpenDialog(NS_ConvertASCIItoUTF16(dialogURL),
+                                   NS_LITERAL_STRING("_blank"),
+                                   NS_LITERAL_STRING("chrome,titlebar,dependent,centerscreen"),
+                                   array, getter_AddRefs(newWindow));
   }
 
   return rv;
@@ -144,8 +147,11 @@ NS_IMETHODIMP nsPrintProgress::GetPrompter(nsIPrompt **_retval)
   NS_ENSURE_ARG_POINTER(_retval);
   *_retval = nullptr;
 
-  if (! m_closeProgress && m_dialog)
-    return m_dialog->GetPrompter(_retval);
+  if (! m_closeProgress && m_dialog) {
+    nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(m_dialog);
+    MOZ_ASSERT(window);
+    return window->GetPrompter(_retval);
+  }
     
   return NS_ERROR_FAILURE;
 }
diff --git a/embedding/components/windowwatcher/nsWindowWatcher.cpp b/embedding/components/windowwatcher/nsWindowWatcher.cpp
index f481efda85b..83ab3951891 100644
--- a/embedding/components/windowwatcher/nsWindowWatcher.cpp
+++ b/embedding/components/windowwatcher/nsWindowWatcher.cpp
@@ -549,9 +549,7 @@ nsWindowWatcher::OpenWindowInternal(nsIDOMWindow* aParent,
   bool hasChromeParent = true;
   if (aParent) {
     // Check if the parent document has chrome privileges.
-    nsCOMPtr<nsIDOMDocument> domdoc;
-    aParent->GetDocument(getter_AddRefs(domdoc));
-    nsCOMPtr<nsIDocument> doc = do_QueryInterface(domdoc);
+    nsIDocument* doc = parentWindow->GetDoc();
     hasChromeParent =
       doc && nsContentUtils::IsChromeDoc(doc) && !openedFromRemoteTab;
   }
@@ -630,11 +628,7 @@ nsWindowWatcher::OpenWindowInternal(nsIDOMWindow* aParent,
     // If the parent trying to open a new window is sandboxed
     // without 'allow-popups', this is not allowed and we fail here.
     if (aParent) {
-      nsCOMPtr<nsIDOMDocument> domdoc;
-      aParent->GetDocument(getter_AddRefs(domdoc));
-      nsCOMPtr<nsIDocument> doc = do_QueryInterface(domdoc);
-
-      if (doc) {
+      if (nsIDocument* doc = parentWindow->GetDoc()) {
         // Save sandbox flags for copying to new browsing context (docShell).
         activeDocsSandboxFlags = doc->GetSandboxFlags();
         if (activeDocsSandboxFlags & SANDBOXED_AUXILIARY_NAVIGATION) {
@@ -1437,11 +1431,11 @@ nsWindowWatcher::URIfromURL(const char* aURL,
                             nsIURI** aURI)
 {
   // Build the URI relative to the entry global.
-  nsCOMPtr<nsIDOMWindow> baseWindow = do_QueryInterface(GetEntryGlobal());
+  nsCOMPtr<nsPIDOMWindow> baseWindow = do_QueryInterface(GetEntryGlobal());
 
   // failing that, build it relative to the parent window, if possible
   if (!baseWindow) {
-    baseWindow = aParent;
+    baseWindow = do_QueryInterface(aParent);
   }
 
   // failing that, use the given URL unmodified. It had better not be relative.
@@ -1450,14 +1444,8 @@ nsWindowWatcher::URIfromURL(const char* aURL,
 
   // get baseWindow's document URI
   if (baseWindow) {
-    nsCOMPtr<nsIDOMDocument> domDoc;
-    baseWindow->GetDocument(getter_AddRefs(domDoc));
-    if (domDoc) {
-      nsCOMPtr<nsIDocument> doc;
-      doc = do_QueryInterface(domDoc);
-      if (doc) {
-        baseURI = doc->GetDocBaseURI();
-      }
+    if (nsIDocument* doc = baseWindow->GetDoc()) {
+      baseURI = doc->GetDocBaseURI();
     }
   }
 
@@ -1647,10 +1635,6 @@ nsWindowWatcher::CalculateChromeFlags(nsIDOMWindow* aParent,
   branch->GetBoolPref("dom.disable_window_open_dialog_feature",
                       &disableDialogFeature);
 
-  bool isFullScreen = false;
-  if (aParent) {
-    aParent->GetFullScreen(&isFullScreen);
-  }
   if (openedFromContentScript) {
     // If the caller context is content, we do not support the
     // dialog feature. See bug 1095236.
@@ -2014,14 +1998,11 @@ nsWindowWatcher::SizeOpenedDocShellItem(nsIDocShellTreeItem* aDocShellItem,
 
   double openerZoom = 1.0;
   if (aParent) {
-    nsCOMPtr<nsIDOMDocument> openerDoc;
-    aParent->GetDocument(getter_AddRefs(openerDoc));
-    if (openerDoc) {
-      nsCOMPtr<nsIDocument> doc = do_QueryInterface(openerDoc);
-      nsIPresShell* shell = doc->GetShell();
-      if (shell) {
-        nsPresContext* presContext = shell->GetPresContext();
-        if (presContext) {
+    nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(aParent);
+    MOZ_ASSERT(piWindow);
+    if (nsIDocument* doc = piWindow->GetDoc()) {
+      if (nsIPresShell* shell = doc->GetShell()) {
+        if (nsPresContext* presContext = shell->GetPresContext()) {
           openerZoom = presContext->GetFullZoom();
         }
       }
@@ -2227,8 +2208,8 @@ nsWindowWatcher::GetWindowOpenLocation(nsIDOMWindow* aParent,
                                        bool aSizeSpecified)
 {
   bool isFullScreen = false;
-  if (aParent) {
-    aParent->GetFullScreen(&isFullScreen);
+  if (nsCOMPtr<nsPIDOMWindow> piParent = do_QueryInterface(aParent)) {
+    isFullScreen = piParent->GetFullScreen();
   }
 
   // Where should we open this?
diff --git a/gfx/2d/BaseRect.h b/gfx/2d/BaseRect.h
index 6812519a260..0caa227afdc 100644
--- a/gfx/2d/BaseRect.h
+++ b/gfx/2d/BaseRect.h
@@ -353,6 +353,18 @@ struct BaseRect {
   T XMost() const { return x + width; }
   T YMost() const { return y + height; }
 
+  // Get the coordinate of the edge on the given side.
+  T Edge(mozilla::Side aSide) const
+  {
+    switch (aSide) {
+      case NS_SIDE_TOP: return Y();
+      case NS_SIDE_RIGHT: return XMost();
+      case NS_SIDE_BOTTOM: return YMost();
+      case NS_SIDE_LEFT: return X();
+    }
+    MOZ_CRASH("Incomplete switch");
+  }
+
   // Moves one edge of the rect without moving the opposite edge.
   void SetLeftEdge(T aX) {
     MOZ_ASSERT(aX <= XMost());
diff --git a/gfx/gl/GLConsts.h b/gfx/gl/GLConsts.h
index fb43c745af3..b400590147a 100644
--- a/gfx/gl/GLConsts.h
+++ b/gfx/gl/GLConsts.h
@@ -5949,6 +5949,4 @@
 #define LOCAL_WGL_VIDEO_OUT_STACKED_FIELDS_1_2               0x20CB
 #define LOCAL_WGL_VIDEO_OUT_STACKED_FIELDS_2_1               0x20CC
 
-
-
 #endif // GLCONSTS_H_
diff --git a/gfx/gl/GLContextProviderWGL.cpp b/gfx/gl/GLContextProviderWGL.cpp
index ffcbbb74f27..b8c62d08681 100644
--- a/gfx/gl/GLContextProviderWGL.cpp
+++ b/gfx/gl/GLContextProviderWGL.cpp
@@ -145,6 +145,9 @@ WGLLibrary::EnsureInitialized()
         return false;
     }
 
+    const GLLibraryLoader::PlatformLookupFunction lookupFunc =
+      (GLLibraryLoader::PlatformLookupFunction) fGetProcAddress;
+
     // Now we can grab all the other symbols that we couldn't without having
     // a context current.
 
@@ -163,16 +166,12 @@ WGLLibrary::EnsureInitialized()
         { nullptr, { nullptr } }
     };
 
-    if (!GLLibraryLoader::LoadSymbols(mOGLLibrary, &pbufferSymbols[0],
-         (GLLibraryLoader::PlatformLookupFunction)fGetProcAddress))
-    {
+    if (!GLLibraryLoader::LoadSymbols(mOGLLibrary, &pbufferSymbols[0], lookupFunc)) {
         // this isn't an error, just means that pbuffers aren't supported
         fCreatePbuffer = nullptr;
     }
 
-    if (!GLLibraryLoader::LoadSymbols(mOGLLibrary, &pixFmtSymbols[0],
-         (GLLibraryLoader::PlatformLookupFunction)fGetProcAddress))
-    {
+    if (!GLLibraryLoader::LoadSymbols(mOGLLibrary, &pixFmtSymbols[0], lookupFunc)) {
         // this isn't an error, just means that we don't have the pixel format extension
         fChoosePixelFormat = nullptr;
     }
@@ -187,18 +186,44 @@ WGLLibrary::EnsureInitialized()
         { nullptr, { nullptr } }
     };
 
-    if (GLLibraryLoader::LoadSymbols(mOGLLibrary, &extensionsSymbols[0],
-        (GLLibraryLoader::PlatformLookupFunction)fGetProcAddress)) {
+    if (GLLibraryLoader::LoadSymbols(mOGLLibrary, &extensionsSymbols[0], lookupFunc)) {
         const char *wglExts = fGetExtensionsString(mWindowDC);
         if (wglExts && HasExtension(wglExts, "WGL_ARB_create_context")) {
-            GLLibraryLoader::LoadSymbols(mOGLLibrary, &robustnessSymbols[0],
-            (GLLibraryLoader::PlatformLookupFunction)fGetProcAddress);
+            GLLibraryLoader::LoadSymbols(mOGLLibrary, &robustnessSymbols[0], lookupFunc);
             if (HasExtension(wglExts, "WGL_ARB_create_context_robustness")) {
                 mHasRobustness = true;
             }
         }
     }
 
+    GLLibraryLoader::SymLoadStruct dxInteropSymbols[] = {
+        { (PRFuncPtr *) &fDXSetResourceShareHandle, { "wglDXSetResourceShareHandleNV", nullptr } },
+        { (PRFuncPtr *) &fDXOpenDevice,             { "wglDXOpenDeviceNV" , nullptr } },
+        { (PRFuncPtr *) &fDXCloseDevice,            { "wglDXCloseDeviceNV" , nullptr } },
+        { (PRFuncPtr *) &fDXRegisterObject,         { "wglDXRegisterObjectNV" , nullptr } },
+        { (PRFuncPtr *) &fDXUnregisterObject,       { "wglDXUnregisterObjectNV" , nullptr } },
+        { (PRFuncPtr *) &fDXObjectAccess,           { "wglDXObjectAccessNV" , nullptr } },
+        { (PRFuncPtr *) &fDXLockObjects,            { "wglDXLockObjectsNV" , nullptr } },
+        { (PRFuncPtr *) &fDXUnlockObjects,          { "wglDXUnlockObjectsNV" , nullptr } },
+        { nullptr, { nullptr } }
+    };
+
+    if (GLLibraryLoader::LoadSymbols(mOGLLibrary, &dxInteropSymbols[0], lookupFunc)) {
+        mHasDXInterop = true;
+        const char *wglExts = fGetExtensionsString(mWindowDC);
+        mHasDXInterop2 = HasExtension(wglExts, "WGL_NV_DX_interop2");
+    } else {
+        NS_ERROR("WGL supports NV_DX_interop without supplying its functions.");
+        fDXSetResourceShareHandle = nullptr;
+        fDXOpenDevice = nullptr;
+        fDXCloseDevice = nullptr;
+        fDXRegisterObject = nullptr;
+        fDXUnregisterObject = nullptr;
+        fDXObjectAccess = nullptr;
+        fDXLockObjects = nullptr;
+        fDXUnlockObjects = nullptr;
+    }
+
     // reset back to the previous context, just in case
     fMakeCurrent(curDC, curCtx);
 
diff --git a/gfx/gl/GLDefs.h b/gfx/gl/GLDefs.h
index 18faa79416b..73d5dd20bf0 100644
--- a/gfx/gl/GLDefs.h
+++ b/gfx/gl/GLDefs.h
@@ -70,4 +70,9 @@
 #define LOCAL_EGL_D3D11_ELSE_D3D9_DISPLAY_ANGLE         ((EGLNativeDisplayType)-2)
 #define LOCAL_EGL_D3D11_ONLY_DISPLAY_ANGLE              ((EGLNativeDisplayType)-3)
 
+// WGL_NV_DX_interop
+#define LOCAL_WGL_ACCESS_READ_ONLY                           0x0000
+#define LOCAL_WGL_ACCESS_READ_WRITE                          0x0001
+#define LOCAL_WGL_ACCESS_WRITE_DISCARD                       0x0002
+
 #endif
diff --git a/gfx/gl/WGLLibrary.h b/gfx/gl/WGLLibrary.h
index f26e57d50a5..007b6df27c9 100644
--- a/gfx/gl/WGLLibrary.h
+++ b/gfx/gl/WGLLibrary.h
@@ -14,10 +14,12 @@ namespace gl {
 class WGLLibrary
 {
 public:
-    WGLLibrary() 
-      : mInitialized(false), 
+    WGLLibrary()
+      : mInitialized(false),
         mOGLLibrary(nullptr),
-        mHasRobustness(false), 
+        mHasRobustness(false),
+        mHasDXInterop(false),
+        mHasDXInterop2(false),
         mWindow (0),
         mWindowDC(0),
         mWindowGLContext(0),
@@ -62,10 +64,45 @@ public:
     typedef HGLRC (WINAPI * PFNWGLCREATECONTEXTATTRIBSPROC) (HDC hdc, HGLRC hShareContext, const int *attribList);
     PFNWGLCREATECONTEXTATTRIBSPROC fCreateContextAttribs;
 
+    // WGL_NV_DX_interop:
+    // BOOL wglDXSetResourceShareHandleNV(void *dxObject, HANDLE shareHandle);
+    typedef BOOL (WINAPI * PFNWGLDXSETRESOURCESHAREHANDLEPROC) (void* dxObject, HANDLE shareHandle);
+    PFNWGLDXSETRESOURCESHAREHANDLEPROC fDXSetResourceShareHandle;
+
+    // HANDLE wglDXOpenDeviceNV(void *dxDevice);
+    typedef HANDLE (WINAPI * PFNWGLDXOPENDEVICEPROC) (void* dxDevice);
+    PFNWGLDXOPENDEVICEPROC fDXOpenDevice;
+
+    // BOOL wglDXCloseDeviceNV(HANDLE hDevice);
+    typedef BOOL (WINAPI * PFNWGLDXCLOSEDEVICEPROC) (HANDLE hDevice);
+    PFNWGLDXCLOSEDEVICEPROC fDXCloseDevice;
+
+    // HANDLE wglDXRegisterObjectNV(HANDLE hDevice, void *dxObject, GLuint name, GLenum type, GLenum access);
+    typedef HANDLE (WINAPI * PFNWGLDXREGISTEROBJECTPROC) (HANDLE hDevice, void* dxObject, GLuint name, GLenum type, GLenum access);
+    PFNWGLDXREGISTEROBJECTPROC fDXRegisterObject;
+
+    // BOOL wglDXUnregisterObjectNV(HANDLE hDevice, HANDLE hObject);
+    typedef BOOL (WINAPI * PFNWGLDXUNREGISTEROBJECT) (HANDLE hDevice, HANDLE hObject);
+    PFNWGLDXUNREGISTEROBJECT fDXUnregisterObject;
+
+    // BOOL wglDXObjectAccessNV(HANDLE hObject, GLenum access);
+    typedef BOOL (WINAPI * PFNWGLDXOBJECTACCESSPROC) (HANDLE hObject, GLenum access);
+    PFNWGLDXOBJECTACCESSPROC fDXObjectAccess;
+
+    // BOOL wglDXLockObjectsNV(HANDLE hDevice, GLint count, HANDLE *hObjects);
+    typedef BOOL (WINAPI * PFNWGLDXLOCKOBJECTSPROC) (HANDLE hDevice, GLint count, HANDLE* hObjects);
+    PFNWGLDXLOCKOBJECTSPROC fDXLockObjects;
+
+    // BOOL wglDXUnlockObjectsNV(HANDLE hDevice, GLint count, HANDLE *hObjects);
+    typedef BOOL (WINAPI * PFNWGLDXUNLOCKOBJECTSPROC) (HANDLE hDevice, GLint count, HANDLE* hObjects);
+    PFNWGLDXUNLOCKOBJECTSPROC fDXUnlockObjects;
+
     bool EnsureInitialized();
     HWND CreateDummyWindow(HDC *aWindowDC = nullptr);
 
     bool HasRobustness() const { return mHasRobustness; }
+    bool HasDXInterop() const { return mHasDXInterop; }
+    bool HasDXInterop2() const { return mHasDXInterop2; }
     bool IsInitialized() const { return mInitialized; }
     HWND GetWindow() const { return mWindow; }
     HDC GetWindowDC() const {return mWindowDC; }
@@ -77,6 +114,8 @@ private:
     bool mInitialized;
     PRLibrary *mOGLLibrary;
     bool mHasRobustness;
+    bool mHasDXInterop;
+    bool mHasDXInterop2;
 
     HWND mWindow;
     HDC mWindowDC;
diff --git a/gfx/layers/apz/src/AsyncPanZoomController.cpp b/gfx/layers/apz/src/AsyncPanZoomController.cpp
index f7d765c56db..be055132c58 100644
--- a/gfx/layers/apz/src/AsyncPanZoomController.cpp
+++ b/gfx/layers/apz/src/AsyncPanZoomController.cpp
@@ -2331,7 +2331,7 @@ void AsyncPanZoomController::AcceptFling(ParentLayerPoint& aVelocity,
       aOverscrollHandoffChain,
       !aHandoff);  // only apply acceleration if this is an initial fling
 
-  float friction = gfxPrefs::APZFlingFriction();
+  float friction = gfxPrefs::APZFlingSnapFriction();
   ParentLayerPoint velocity(mX.GetVelocity(), mY.GetVelocity());
   ParentLayerPoint predictedDelta;
   // "-velocity / log(1.0 - friction)" is the integral of the deceleration
diff --git a/gfx/thebes/gfxPrefs.h b/gfx/thebes/gfxPrefs.h
index 46234622d4f..63b2fd9aafc 100644
--- a/gfx/thebes/gfxPrefs.h
+++ b/gfx/thebes/gfxPrefs.h
@@ -162,6 +162,7 @@ private:
   DECL_GFX_PREF(Live, "apz.fling_curve_threshold_inches_per_ms", APZCurveThreshold, float, -1.0f);
   DECL_GFX_PREF(Once, "apz.fling_friction",                    APZFlingFriction, float, 0.002f);
   DECL_GFX_PREF(Live, "apz.fling_repaint_interval",            APZFlingRepaintInterval, int32_t, 75);
+  DECL_GFX_PREF(Once, "apz.fling_snap_friction",               APZFlingSnapFriction, float, 0.015f);
   DECL_GFX_PREF(Once, "apz.fling_stop_on_tap_threshold",       APZFlingStopOnTapThreshold, float, 0.05f);
   DECL_GFX_PREF(Once, "apz.fling_stopped_threshold",           APZFlingStoppedThreshold, float, 0.01f);
   DECL_GFX_PREF(Once, "apz.highlight_checkerboarded_areas",    APZHighlightCheckerboardedAreas, bool, false);
diff --git a/ipc/chromium/src/chrome/common/ipc_message.cc b/ipc/chromium/src/chrome/common/ipc_message.cc
index 609e5f3a36b..ab68ea7f46a 100644
--- a/ipc/chromium/src/chrome/common/ipc_message.cc
+++ b/ipc/chromium/src/chrome/common/ipc_message.cc
@@ -25,10 +25,12 @@ namespace IPC {
 //------------------------------------------------------------------------------
 
 Message::~Message() {
+  MOZ_COUNT_DTOR(IPC::Message);
 }
 
 Message::Message()
     : Pickle(sizeof(Header)) {
+  MOZ_COUNT_CTOR(IPC::Message);
   header()->routing = header()->type = header()->flags = 0;
 #if defined(OS_POSIX)
   header()->num_fds = 0;
@@ -44,6 +46,7 @@ Message::Message()
 Message::Message(int32_t routing_id, msgid_t type, PriorityValue priority,
                  MessageCompression compression, const char* const aName)
     : Pickle(sizeof(Header)) {
+  MOZ_COUNT_CTOR(IPC::Message);
   header()->routing = routing_id;
   header()->type = type;
   header()->flags = priority;
@@ -69,10 +72,12 @@ Message::Message(int32_t routing_id, msgid_t type, PriorityValue priority,
 }
 
 Message::Message(const char* data, int data_len) : Pickle(data, data_len) {
+  MOZ_COUNT_CTOR(IPC::Message);
   InitLoggingVariables();
 }
 
 Message::Message(const Message& other) : Pickle(other) {
+  MOZ_COUNT_CTOR(IPC::Message);
   InitLoggingVariables(other.name_);
 #if defined(OS_POSIX)
   file_descriptor_set_ = other.file_descriptor_set_;
@@ -85,6 +90,7 @@ Message::Message(const Message& other) : Pickle(other) {
 }
 
 Message::Message(Message&& other) : Pickle(mozilla::Move(other)) {
+  MOZ_COUNT_CTOR(IPC::Message);
   InitLoggingVariables(other.name_);
 #if defined(OS_POSIX)
   file_descriptor_set_ = other.file_descriptor_set_.forget();
diff --git a/ipc/glue/MessageChannel.cpp b/ipc/glue/MessageChannel.cpp
index a20409cf37e..1388b6502b9 100644
--- a/ipc/glue/MessageChannel.cpp
+++ b/ipc/glue/MessageChannel.cpp
@@ -991,6 +991,7 @@ MessageChannel::Send(Message* aMsg, Message* aReply)
 bool
 MessageChannel::Call(Message* aMsg, Message* aReply)
 {
+    nsAutoPtr<Message> msg(aMsg);
     AssertWorkerThread();
     mMonitor->AssertNotCurrentThreadOwns();
 
@@ -1000,11 +1001,11 @@ MessageChannel::Call(Message* aMsg, Message* aReply)
 
     // This must come before MonitorAutoLock, as its destructor acquires the
     // monitor lock.
-    CxxStackFrame cxxframe(*this, OUT_MESSAGE, aMsg);
+    CxxStackFrame cxxframe(*this, OUT_MESSAGE, msg);
 
     MonitorAutoLock lock(*mMonitor);
     if (!Connected()) {
-        ReportConnectionError("MessageChannel::Call", aMsg);
+        ReportConnectionError("MessageChannel::Call", msg);
         return false;
     }
 
@@ -1013,9 +1014,7 @@ MessageChannel::Call(Message* aMsg, Message* aReply)
                "cannot issue Interrupt call while blocked on sync request");
     IPC_ASSERT(!DispatchingSyncMessage(),
                "violation of sync handler invariant");
-    IPC_ASSERT(aMsg->is_interrupt(), "can only Call() Interrupt messages here");
-
-    nsAutoPtr<Message> msg(aMsg);
+    IPC_ASSERT(msg->is_interrupt(), "can only Call() Interrupt messages here");
 
     msg->set_seqno(NextSeqno());
     msg->set_interrupt_remote_stack_depth_guess(mRemoteStackDepthGuess);
diff --git a/js/src/asmjs/AsmJSModule.cpp b/js/src/asmjs/AsmJSModule.cpp
index 4be580f6a8c..6746978f006 100644
--- a/js/src/asmjs/AsmJSModule.cpp
+++ b/js/src/asmjs/AsmJSModule.cpp
@@ -314,10 +314,9 @@ AsmJSModule::finish(ExclusiveContext* cx, TokenStream& tokenStream, MacroAssembl
     MOZ_ASSERT(masm.preBarrierTableBytes() == 0);
     MOZ_ASSERT(!masm.hasSelfReference());
 
-    // Copy over metadata, making sure to update all offsets on ARM.
-
-    staticLinkData_.interruptExitOffset = masm.actualOffset(interruptLabel.offset());
-    staticLinkData_.outOfBoundsExitOffset = masm.actualOffset(outOfBoundsLabel.offset());
+    // Copy over metadata.
+    staticLinkData_.interruptExitOffset = interruptLabel.offset();
+    staticLinkData_.outOfBoundsExitOffset = outOfBoundsLabel.offset();
 
     // Heap-access metadata used for link-time patching and fault-handling.
     heapAccesses_ = masm.extractAsmJSHeapAccesses();
@@ -325,30 +324,6 @@ AsmJSModule::finish(ExclusiveContext* cx, TokenStream& tokenStream, MacroAssembl
     // Call-site metadata used for stack unwinding.
     callSites_ = masm.extractCallSites();
 
-#if defined(JS_CODEGEN_ARM)
-    // ARM requires the offsets to be updated.
-    pod.functionBytes_ = masm.actualOffset(pod.functionBytes_);
-    for (size_t i = 0; i < heapAccesses_.length(); i++) {
-        AsmJSHeapAccess& a = heapAccesses_[i];
-        a.setInsnOffset(masm.actualOffset(a.insnOffset()));
-    }
-    for (unsigned i = 0; i < numExportedFunctions(); i++) {
-        if (!exportedFunction(i).isChangeHeap())
-            exportedFunction(i).updateCodeOffset(masm);
-    }
-    for (unsigned i = 0; i < numExits(); i++)
-        exit(i).updateOffsets(masm);
-    for (size_t i = 0; i < callSites_.length(); i++) {
-        CallSite& c = callSites_[i];
-        c.setReturnAddressOffset(masm.actualOffset(c.returnAddressOffset()));
-    }
-    for (size_t i = 0; i < codeRanges_.length(); i++) {
-        codeRanges_[i].updateOffsets(masm);
-        MOZ_ASSERT_IF(i > 0, codeRanges_[i - 1].end() <= codeRanges_[i].begin());
-    }
-    for (size_t i = 0; i < builtinThunkOffsets_.length(); i++)
-        builtinThunkOffsets_[i] = masm.actualOffset(builtinThunkOffsets_[i]);
-#endif
     MOZ_ASSERT(pod.functionBytes_ % AsmJSPageSize == 0);
 
     // Absolute link metadata: absolute addresses that refer to some fixed
@@ -356,7 +331,7 @@ AsmJSModule::finish(ExclusiveContext* cx, TokenStream& tokenStream, MacroAssembl
     AbsoluteLinkArray& absoluteLinks = staticLinkData_.absoluteLinks;
     for (size_t i = 0; i < masm.numAsmJSAbsoluteLinks(); i++) {
         AsmJSAbsoluteLink src = masm.asmJSAbsoluteLink(i);
-        if (!absoluteLinks[src.target].append(masm.actualOffset(src.patchAt.offset())))
+        if (!absoluteLinks[src.target].append(src.patchAt.offset()))
             return false;
     }
 
@@ -368,7 +343,7 @@ AsmJSModule::finish(ExclusiveContext* cx, TokenStream& tokenStream, MacroAssembl
     for (size_t i = 0; i < masm.numCodeLabels(); i++) {
         CodeLabel src = masm.codeLabel(i);
         int32_t labelOffset = src.dest()->offset();
-        int32_t targetOffset = masm.actualOffset(src.src()->offset());
+        int32_t targetOffset = src.src()->offset();
         // The patched uses of a label embed a linked list where the
         // to-be-patched immediate is the offset of the next to-be-patched
         // instruction.
@@ -420,15 +395,6 @@ AsmJSModule::finish(ExclusiveContext* cx, TokenStream& tokenStream, MacroAssembl
     }
 #endif
 
-#if defined(MOZ_VTUNE) || defined(JS_ION_PERF)
-    // Fix up the code offsets.
-    for (size_t i = 0; i < profiledFunctions_.length(); i++) {
-        ProfiledFunction& pf = profiledFunctions_[i];
-        pf.pod.startCodeOffset = masm.actualOffset(pf.pod.startCodeOffset);
-        pf.pod.endCodeOffset = masm.actualOffset(pf.pod.endCodeOffset);
-    }
-#endif
-
     return true;
 }
 
@@ -1437,29 +1403,6 @@ AsmJSModule::CodeRange::CodeRange(AsmJSExit::BuiltinKind builtin, uint32_t begin
     MOZ_ASSERT(profilingReturn_ < end_);
 }
 
-void
-AsmJSModule::CodeRange::updateOffsets(jit::MacroAssembler& masm)
-{
-    uint32_t entryBefore = 0;
-    uint32_t profilingJumpBefore = 0;
-    uint32_t profilingEpilogueBefore = 0;
-    if (isFunction()) {
-        entryBefore = entry();
-        profilingJumpBefore = profilingJump();
-        profilingEpilogueBefore = profilingEpilogue();
-    }
-
-    begin_ = masm.actualOffset(begin_);
-    profilingReturn_ = masm.actualOffset(profilingReturn_);
-    end_ = masm.actualOffset(end_);
-
-    if (isFunction()) {
-        setDeltas(masm.actualOffset(entryBefore),
-                  masm.actualOffset(profilingJumpBefore),
-                  masm.actualOffset(profilingEpilogueBefore));
-    }
-}
-
 #if defined(MOZ_VTUNE) || defined(JS_ION_PERF)
 size_t
 AsmJSModule::ProfiledFunction::serializedSize() const
diff --git a/js/src/asmjs/AsmJSModule.h b/js/src/asmjs/AsmJSModule.h
index 1afc0661414..ded2a072ee0 100644
--- a/js/src/asmjs/AsmJSModule.h
+++ b/js/src/asmjs/AsmJSModule.h
@@ -402,10 +402,6 @@ class AsmJSModule
             MOZ_ASSERT(!jitCodeOffset_);
             jitCodeOffset_ = off;
         }
-        void updateOffsets(jit::MacroAssembler& masm) {
-            interpCodeOffset_ = masm.actualOffset(interpCodeOffset_);
-            jitCodeOffset_ = masm.actualOffset(jitCodeOffset_);
-        }
 
         size_t serializedSize() const;
         uint8_t* serialize(uint8_t* cursor) const;
@@ -520,10 +516,6 @@ class AsmJSModule
             MOZ_ASSERT(pod.codeOffset_ == UINT32_MAX);
             pod.codeOffset_ = off;
         }
-        void updateCodeOffset(jit::MacroAssembler& masm) {
-            MOZ_ASSERT(!isChangeHeap());
-            pod.codeOffset_ = masm.actualOffset(pod.codeOffset_);
-        }
 
         unsigned numArgs() const {
             MOZ_ASSERT(!isChangeHeap());
@@ -578,7 +570,6 @@ class AsmJSModule
         CodeRange(Kind kind, uint32_t begin, uint32_t end);
         CodeRange(Kind kind, uint32_t begin, uint32_t profilingReturn, uint32_t end);
         CodeRange(AsmJSExit::BuiltinKind builtin, uint32_t begin, uint32_t pret, uint32_t end);
-        void updateOffsets(jit::MacroAssembler& masm);
 
         Kind kind() const { return Kind(u.kind_); }
         bool isFunction() const { return kind() == Function; }
diff --git a/js/src/asmjs/AsmJSValidate.cpp b/js/src/asmjs/AsmJSValidate.cpp
index 79ea4b29952..67d1a40e136 100644
--- a/js/src/asmjs/AsmJSValidate.cpp
+++ b/js/src/asmjs/AsmJSValidate.cpp
@@ -1505,7 +1505,7 @@ class MOZ_STACK_CLASS ModuleValidator
                 AsmJSModule::RelativeLink link(AsmJSModule::RelativeLink::RawPointer);
                 link.patchAtOffset = tableBaseOffset + elemIndex * sizeof(uint8_t*);
                 Label* entry = functionEntry(table.elem(elemIndex).funcIndex());
-                link.targetOffset = masm().actualOffset(entry->offset());
+                link.targetOffset = entry->offset();
                 if (!module_->addRelativeLink(link))
                     return false;
             }
diff --git a/js/src/frontend/Parser.cpp b/js/src/frontend/Parser.cpp
index 4185930e76a..03062ba6478 100644
--- a/js/src/frontend/Parser.cpp
+++ b/js/src/frontend/Parser.cpp
@@ -4068,57 +4068,6 @@ Parser<SyntaxParseHandler>::pushLetScope(HandleStaticBlockObject blockObj, AutoP
     return SyntaxParseHandler::NodeFailure;
 }
 
-/*
- * Parse a let block statement.
- * In both cases, bindings are not hoisted to the top of the enclosing block
- * and thus must be carefully injected between variables() and the let body.
- */
-template <typename ParseHandler>
-typename ParseHandler::Node
-Parser<ParseHandler>::deprecatedLetBlock(YieldHandling yieldHandling)
-{
-    MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_LET));
-
-    RootedStaticBlockObject blockObj(context, StaticBlockObject::create(context));
-    if (!blockObj)
-        return null();
-    // Initialize the enclosing scope manually for the call to |variables|
-    // below.
-    blockObj->initEnclosingScopeFromParser(pc->innermostStaticScope());
-
-    uint32_t begin = pos().begin;
-
-    MUST_MATCH_TOKEN(TOK_LP, JSMSG_PAREN_BEFORE_LET);
-
-    Node vars = variables(yieldHandling, PNK_LET, NotInForInit, nullptr, blockObj, DontHoistVars);
-    if (!vars)
-        return null();
-
-    MUST_MATCH_TOKEN(TOK_RP, JSMSG_PAREN_AFTER_LET);
-
-    AutoPushStmtInfoPC stmtInfo(*this, StmtType::BLOCK);
-    Node block = pushLetScope(blockObj, stmtInfo);
-    if (!block)
-        return null();
-
-    MUST_MATCH_TOKEN(TOK_LC, JSMSG_CURLY_BEFORE_LET);
-
-    Node expr = statements(yieldHandling);
-    if (!expr)
-        return null();
-    MUST_MATCH_TOKEN_MOD(TOK_RC, TokenStream::Operand, JSMSG_CURLY_AFTER_LET);
-
-    addTelemetry(JSCompartment::DeprecatedLetBlock);
-    if (!report(ParseWarning, pc->sc->strict(), expr, JSMSG_DEPRECATED_LET_BLOCK))
-        return null();
-
-    handler.setLexicalScopeBody(block, expr);
-
-    TokenPos letPos(begin, pos().end);
-
-    return handler.newLetBlock(vars, block, letPos);
-}
-
 template <typename ParseHandler>
 typename ParseHandler::Node
 Parser<ParseHandler>::blockStatement(YieldHandling yieldHandling)
@@ -4532,45 +4481,6 @@ Parser<SyntaxParseHandler>::lexicalDeclaration(YieldHandling, bool)
     return SyntaxParseHandler::NodeFailure;
 }
 
-template <>
-ParseNode*
-Parser<FullParseHandler>::letDeclarationOrBlock(YieldHandling yieldHandling)
-{
-    handler.disableSyntaxParser();
-
-    /* Check for a let statement. */
-    TokenKind tt;
-    if (!tokenStream.peekToken(&tt))
-        return null();
-    if (tt == TOK_LP) {
-        ParseNode* node = deprecatedLetBlock(yieldHandling);
-        if (!node)
-            return nullptr;
-
-        MOZ_ASSERT(node->isKind(PNK_LETBLOCK));
-        MOZ_ASSERT(node->isArity(PN_BINARY));
-        return node;
-    }
-
-    ParseNode* decl = lexicalDeclaration(yieldHandling, /* isConst = */ false);
-    if (!decl)
-        return nullptr;
-
-    // let-declarations at global scope are currently treated as plain old var.
-    // See bug 589199.
-    MOZ_ASSERT(decl->isKind(PNK_LET) || decl->isKind(PNK_VAR));
-    MOZ_ASSERT(decl->isArity(PN_LIST));
-    return decl;
-}
-
-template <>
-SyntaxParseHandler::Node
-Parser<SyntaxParseHandler>::letDeclarationOrBlock(YieldHandling yieldHandling)
-{
-    JS_ALWAYS_FALSE(abortIfSyntaxParser());
-    return SyntaxParseHandler::NodeFailure;
-}
-
 template<>
 ParseNode*
 Parser<FullParseHandler>::newBoundImportForCurrentName()
@@ -6871,13 +6781,12 @@ Parser<ParseHandler>::statement(YieldHandling yieldHandling, bool canHaveDirecti
 
       // LexicalDeclaration[In, ?Yield]
       case TOK_LET:
-        // [In] is the default behavior, because for-loops currently specially
-        // parse their heads to handle |in| in this situation.
-        return letDeclarationOrBlock(yieldHandling);
       case TOK_CONST:
         if (!abortIfSyntaxParser())
             return null();
-        return lexicalDeclaration(yieldHandling, /* isConst = */ true);
+        // [In] is the default behavior, because for-loops currently specially
+        // parse their heads to handle |in| in this situation.
+        return lexicalDeclaration(yieldHandling, /* isConst = */ tt == TOK_CONST);
 
       // ImportDeclaration (only inside modules)
       case TOK_IMPORT:
diff --git a/js/src/frontend/Parser.h b/js/src/frontend/Parser.h
index 0b26b92b1a0..35767558698 100644
--- a/js/src/frontend/Parser.h
+++ b/js/src/frontend/Parser.h
@@ -682,7 +682,6 @@ class Parser : private JS::AutoGCRooter, public StrictModeGetter
     Node debuggerStatement();
 
     Node lexicalDeclaration(YieldHandling yieldHandling, bool isConst);
-    Node letDeclarationOrBlock(YieldHandling yieldHandling);
     Node importDeclaration();
     Node exportDeclaration();
     Node expressionStatement(YieldHandling yieldHandling,
@@ -755,7 +754,6 @@ class Parser : private JS::AutoGCRooter, public StrictModeGetter
     Node generatorComprehension(uint32_t begin);
 
     bool argumentList(YieldHandling yieldHandling, Node listNode, bool* isSpread);
-    Node deprecatedLetBlock(YieldHandling yieldHandling);
     Node destructuringExpr(YieldHandling yieldHandling, BindData<ParseHandler>* data,
                            TokenKind tt);
     Node destructuringExprWithoutYield(YieldHandling yieldHandling, BindData<ParseHandler>* data,
diff --git a/js/src/irregexp/NativeRegExpMacroAssembler.cpp b/js/src/irregexp/NativeRegExpMacroAssembler.cpp
index aab0fb4de2a..c773e0ab464 100644
--- a/js/src/irregexp/NativeRegExpMacroAssembler.cpp
+++ b/js/src/irregexp/NativeRegExpMacroAssembler.cpp
@@ -470,10 +470,8 @@ NativeRegExpMacroAssembler::GenerateCode(JSContext* cx, bool match_only)
     for (size_t i = 0; i < labelPatches.length(); i++) {
         LabelPatch& v = labelPatches[i];
         MOZ_ASSERT(!v.label);
-        v.patchOffset.fixup(&masm);
-        uintptr_t offset = masm.actualOffset(v.labelOffset);
         Assembler::PatchDataWithValueCheck(CodeLocationLabel(code, v.patchOffset),
-                                           ImmPtr(code->raw() + offset),
+                                           ImmPtr(code->raw() + v.labelOffset),
                                            ImmPtr(0));
     }
 
diff --git a/js/src/jit-test/lib/syntax.js b/js/src/jit-test/lib/syntax.js
index 2d0dce54053..3df762a810b 100644
--- a/js/src/jit-test/lib/syntax.js
+++ b/js/src/jit-test/lib/syntax.js
@@ -1154,22 +1154,6 @@ function test_syntax(postfixes, check_error, ignore_opts) {
 
   // ==== Legacy ====
 
-  // let statement
-
-  test("let ( ");
-  test("let ( x ");
-  test("let ( x = ");
-  test("let ( x = 1 ");
-  test("let ( x = 1, ");
-  test("let ( x = 1, y ");
-  test("let ( x = 1, y = ");
-  test("let ( x = 1, y = 2 ");
-  test("let ( x = 1, y = 2 ) ");
-  test("let ( x = 1, y = 2 ) { ");
-  test("let ( x = 1, y = 2 ) { x ");
-  test("let ( x = 1, y = 2 ) { x; ");
-  test("let ( x = 1, y = 2 ) { x; } ");
-
   // Expression closures
 
   test("function f() 1 ");
diff --git a/js/src/jit-test/tests/arguments/bug956173.js b/js/src/jit-test/tests/arguments/bug956173.js
index 4c504fdb509..d88efaa7abf 100644
--- a/js/src/jit-test/tests/arguments/bug956173.js
+++ b/js/src/jit-test/tests/arguments/bug956173.js
@@ -1,5 +1,6 @@
 function foo() {
-    let (x=arguments) {
+    {
+      let x=arguments;
       return function() { return x; };
     }
 }
diff --git a/js/src/jit-test/tests/auto-regress/bug1147907.js b/js/src/jit-test/tests/auto-regress/bug1147907.js
index 93c1920d4e9..4d34f599909 100644
--- a/js/src/jit-test/tests/auto-regress/bug1147907.js
+++ b/js/src/jit-test/tests/auto-regress/bug1147907.js
@@ -8,6 +8,7 @@ var evalInFrame = (function (global) {
   };
 })(this);
 var x = 5;
-let (x = eval("x++")) {
+{
+  let x = eval("this.x++");
   evalInFrame(0, ("for (var x = 0; x < 3; ++x) { (function(){})() } "))
 }
diff --git a/js/src/jit-test/tests/auto-regress/bug475658.js b/js/src/jit-test/tests/auto-regress/bug475658.js
deleted file mode 100644
index fab19663680..00000000000
--- a/js/src/jit-test/tests/auto-regress/bug475658.js
+++ /dev/null
@@ -1,9 +0,0 @@
-// Binary: cache/js-dbg-32-6739e046d870-linux
-// Flags: -j
-//
-for each (b in [2, new Number(7), 2, {}, 2, 2]) {
-    let (f = function (g) {for each (let h in [{}, {}, {}, 4, 4, {}]) {}}) {
-        f();
-    }
-    [new Number(1) for each (e in [{}, {}])];
-}
diff --git a/js/src/jit-test/tests/auto-regress/bug496251.js b/js/src/jit-test/tests/auto-regress/bug496251.js
deleted file mode 100644
index cb5fe3a6c4f..00000000000
--- a/js/src/jit-test/tests/auto-regress/bug496251.js
+++ /dev/null
@@ -1,10 +0,0 @@
-// Binary: cache/js-dbg-32-9d6f5ab54933-linux
-// Flags: -j
-//
-let (z = {}) {
-    for (var i = 0; i < 4; ++i) {
-        for each (var e in [{}, 1, {}]) {
-            +(function () z)();
-        }
-    }
-}
diff --git a/js/src/jit-test/tests/auto-regress/bug521163.js b/js/src/jit-test/tests/auto-regress/bug521163.js
index f435b73da70..1c018645d60 100644
--- a/js/src/jit-test/tests/auto-regress/bug521163.js
+++ b/js/src/jit-test/tests/auto-regress/bug521163.js
@@ -4,7 +4,8 @@
 // Flags:
 //
 for (c in [0]) {
-    let(c = __defineGetter__("", function(){})) {
+    {
+        let c = __defineGetter__("", function(){});
         eval("function w(){}")++
     }
 }
diff --git a/js/src/jit-test/tests/basic/bug590006.js b/js/src/jit-test/tests/basic/bug590006.js
index 9654663f8b1..233aeb29283 100644
--- a/js/src/jit-test/tests/basic/bug590006.js
+++ b/js/src/jit-test/tests/basic/bug590006.js
@@ -1,7 +1,8 @@
 function f() {
     var ret;
     for (var i = 0; i < 10; ++i) {
-        let (local = 3) {
+        {
+            let local = 3;
             ret = function() { print(local++); }
         }
     }
diff --git a/js/src/jit-test/tests/basic/bug601398.js b/js/src/jit-test/tests/basic/bug601398.js
index e6276eeffc8..f3eaddccbf4 100644
--- a/js/src/jit-test/tests/basic/bug601398.js
+++ b/js/src/jit-test/tests/basic/bug601398.js
@@ -1,6 +1,7 @@
 (function () {
     try {} finally {
-        let(z) {
+        {
+            let z;
             return;
         }
     }
diff --git a/js/src/jit-test/tests/basic/bug601401.js b/js/src/jit-test/tests/basic/bug601401.js
index 0ee7dda7dee..5c4a4f36c40 100644
--- a/js/src/jit-test/tests/basic/bug601401.js
+++ b/js/src/jit-test/tests/basic/bug601401.js
@@ -1,5 +1,6 @@
-let(e) {
+{
+    let e;
     with({}) try {} catch (x) {} finally {
-        let(y) {}
+        { let y; }
     }
 }
diff --git a/js/src/jit-test/tests/basic/bug639311.js b/js/src/jit-test/tests/basic/bug639311.js
index 0ee9815388f..277d0c3d108 100644
--- a/js/src/jit-test/tests/basic/bug639311.js
+++ b/js/src/jit-test/tests/basic/bug639311.js
@@ -14,5 +14,5 @@ try {
   delete this.Math
 }
 gc()
-Reflect.parse("let(x){}")
+Reflect.parse("{ let x; }")
 gc()
diff --git a/js/src/jit-test/tests/basic/bug646968-7.js b/js/src/jit-test/tests/basic/bug646968-7.js
index 599b7fd60ba..7fac119f565 100644
--- a/js/src/jit-test/tests/basic/bug646968-7.js
+++ b/js/src/jit-test/tests/basic/bug646968-7.js
@@ -2,8 +2,9 @@ load(libdir + "evalInFrame.js");
 
 function test(s) {
     eval(s);
-    let (y = evalInFrame(0, '3'), x = x) {
-	assertEq(x, 5);
+    {
+      let y = evalInFrame(0, '3'), x = x0;
+	    assertEq(x, 5);
     }
 }
-test('var x = 5;');
+test('var x0= 5;');
diff --git a/js/src/jit-test/tests/basic/bug646968-8.js b/js/src/jit-test/tests/basic/bug646968-8.js
index 8b58da6f77a..9214f0798f0 100644
--- a/js/src/jit-test/tests/basic/bug646968-8.js
+++ b/js/src/jit-test/tests/basic/bug646968-8.js
@@ -1,7 +1,8 @@
 load(libdir + "evalInFrame.js");
 
 var x = 5;
-let (x = eval("x++")) {
+{
+    let x = eval("this.x++");
     assertEq(evalInFrame(0, "x"), 5);
 }
 assertEq(x, 6);
diff --git a/js/src/jit-test/tests/basic/bug667504-syntax.js b/js/src/jit-test/tests/basic/bug667504-syntax.js
index e73350e411d..c2e926d9639 100644
--- a/js/src/jit-test/tests/basic/bug667504-syntax.js
+++ b/js/src/jit-test/tests/basic/bug667504-syntax.js
@@ -1,3 +1,2 @@
 for (var x in x)
-let(x) {}
 function x() {}
diff --git a/js/src/jit-test/tests/basic/bug727921.js b/js/src/jit-test/tests/basic/bug727921.js
index 88e6773a7df..14a4b689f90 100644
--- a/js/src/jit-test/tests/basic/bug727921.js
+++ b/js/src/jit-test/tests/basic/bug727921.js
@@ -1,5 +1,6 @@
 (function() {
-    let(d) {
+    {
+        let d;
         yield
     }
 })()
diff --git a/js/src/jit-test/tests/basic/bug806522.js b/js/src/jit-test/tests/basic/bug806522.js
index e839de78dac..1507276c1a1 100644
--- a/js/src/jit-test/tests/basic/bug806522.js
+++ b/js/src/jit-test/tests/basic/bug806522.js
@@ -2,6 +2,6 @@ load(libdir + "asserts.js");
 
 var g = evalcx("lazy");
 assertThrowsInstanceOf(
-    () => evaluate("let (eval) {eval()}", {global: g}),
+    () => evaluate("{ let eval; eval()}", {global: g}),
     g.TypeError); // eval is not a function
-assertEq(evaluate("let (eval = parseInt) {eval()}", {global: g}), NaN);
+assertEq(evaluate("{ let eval = parseInt; eval()}", {global: g}), NaN);
diff --git a/js/src/jit-test/tests/basic/destructuring-default.js b/js/src/jit-test/tests/basic/destructuring-default.js
index c6525238ac4..545a1f186d2 100644
--- a/js/src/jit-test/tests/basic/destructuring-default.js
+++ b/js/src/jit-test/tests/basic/destructuring-default.js
@@ -92,17 +92,6 @@ function testThrow(pattern, input) {
 }
 testAll(testThrow);
 
-// XXX: Support for let blocks will be removed in bug 1023609.
-// However, they test a special code path in destructuring assignment so having
-// these tests here for now seems like a good idea.
-function testLetBlock(pattern, input) {
-  return new Function('input',
-    'let (' + pattern + ' = input)' +
-    '{ return [a, b, c, d, e, f]; }'
-  )(input);
-}
-testAll(testLetBlock);
-
 // test global const
 const [ca = 1, cb = 2] = [];
 assertEq(ca, 1);
diff --git a/js/src/jit-test/tests/basic/destructuring-rest.js b/js/src/jit-test/tests/basic/destructuring-rest.js
index 6c08161299f..30ac1b002d9 100644
--- a/js/src/jit-test/tests/basic/destructuring-rest.js
+++ b/js/src/jit-test/tests/basic/destructuring-rest.js
@@ -126,15 +126,3 @@ function testThrow(pattern, input, binding) {
   )(input);
 }
 testDeclaration(testThrow);
-
-// XXX: Support for let blocks will be removed in bug 1023609.
-// However, they test a special code path in destructuring assignment so having
-// these tests here for now seems like a good idea.
-function testLetBlock(pattern, input, binding) {
-  binding = binding || 'rest';
-  return new Function('input',
-    'let (' + pattern + ' = input)' +
-    '{ return ' + binding + '; }'
-  )(input);
-}
-testDeclaration(testLetBlock);
diff --git a/js/src/jit-test/tests/basic/eif-generator.js b/js/src/jit-test/tests/basic/eif-generator.js
index 79e78ec8830..99a45bf5a5d 100644
--- a/js/src/jit-test/tests/basic/eif-generator.js
+++ b/js/src/jit-test/tests/basic/eif-generator.js
@@ -1,11 +1,13 @@
 load(libdir + "evalInFrame.js");
 
 function f() {
-    let (x = 1) {
+    {
+        let x = 1;
         while (true) {
             yield evalInFrame(0, "x");
             x++;
-            let (y = 1) {
+            {
+                let y = 1;
                 yield evalInFrame(0, "++y");
                 yield evalInFrame(0, "++y");
             }
@@ -32,7 +34,8 @@ gen = null;
 gc();
 
 function g() {
-    let (x = 1) {
+    {
+        let x = 1;
         while (true) {
             var inner = function (inc) { x += inc; return evalInFrame(0, "x") };
             assertEq(inner(0), x);
diff --git a/js/src/jit-test/tests/basic/expression-autopsy.js b/js/src/jit-test/tests/basic/expression-autopsy.js
index 3d89a87f869..3352226dae6 100644
--- a/js/src/jit-test/tests/basic/expression-autopsy.js
+++ b/js/src/jit-test/tests/basic/expression-autopsy.js
@@ -39,20 +39,10 @@ function check(expr, expected=expr) {
             Function("o", "undef", "function myfunc() { return o + undef; }\n" + statement),
             // Let definitions in a block
             Function("{ let o, undef;\n" + statement + "}"),
-            // Let block
-            Function("let (o, undef) { " + statement + " }"),
-            // Let block with some other variables
-            Function("var v1, v2; let (o, undef) { " + statement + " }"),
-            // Shadowed let block
-            Function("o", "undef", "let (o, undef) { " + statement + " }"),
             // Let in a switch
             Function("var x = 4; switch (x) { case 4: let o, undef;" + statement + "\ncase 6: break;}"),
-            // The more lets the merrier
-            Function("let (x=4, y=5) { x + y; }\nlet (a, b, c) { a + b - c; }\nlet (o, undef) {" + statement + " }"),
-            // Let destructuring
-            Function("o", "undef", "let ([] = []) {} let (o, undef) { " + statement + " }"),
             // Try-catch blocks
-            Function("o", "undef", "try { let q = 4; try { let p = 4; } catch (e) {} } catch (e) {} let (o, undef) { " + statement + " }")
+            Function("o", "undef", "try { let q = 4; try { let p = 4; } catch (e) {} } catch (e) {} { let o, undef; " + statement + " }")
         ];
 
         try {
@@ -112,7 +102,7 @@ check("o[- (o)]");
 check_one("6", (function () { 6() }), " is not a function");
 check_one("0", (function () { Array.prototype.reverse.call('123'); }), " is read-only");
 check_one("(intermediate value)[Symbol.iterator](...).next(...).value",
-          function () { ieval("let (x) { var [a, b, [c0, c1]] = [x, x, x]; }") }, " is undefined");
+          function () { ieval("{ let x; var [a, b, [c0, c1]] = [x, x, x]; }") }, " is undefined");
 check_one("void 1", function() { (void 1)(); }, " is not a function");
 check_one("void o[1]", function() { var o = []; (void o[1])() }, " is not a function");
 
diff --git a/js/src/jit-test/tests/basic/testAliasedLet.js b/js/src/jit-test/tests/basic/testAliasedLet.js
index c07cbea2e5c..3ab016999ba 100644
--- a/js/src/jit-test/tests/basic/testAliasedLet.js
+++ b/js/src/jit-test/tests/basic/testAliasedLet.js
@@ -1,5 +1,6 @@
 function f() {
-    let (x, y, z) {
+    {
+        let x, y, z;
         eval('x = 1; y = 2; z = 3');
         for (var i = 0; i < 10000; ++i) {
             assertEq(x, 1);
diff --git a/js/src/jit-test/tests/basic/testBadLetBodyWithArguments.js b/js/src/jit-test/tests/basic/testBadLetBodyWithArguments.js
deleted file mode 100644
index 7a8224c9cdc..00000000000
--- a/js/src/jit-test/tests/basic/testBadLetBodyWithArguments.js
+++ /dev/null
@@ -1,6 +0,0 @@
-// |jit-test| error:SyntaxError
-
-function test() {
-    arguments;
-    let (arguments);
-}
diff --git a/js/src/jit-test/tests/basic/testBug703857.js b/js/src/jit-test/tests/basic/testBug703857.js
index 0f230e461ab..dcdcc1e1f15 100644
--- a/js/src/jit-test/tests/basic/testBug703857.js
+++ b/js/src/jit-test/tests/basic/testBug703857.js
@@ -3,7 +3,8 @@ function ownProperties() {
     var props = {};
     var r = function () {};
     for (var a in r) {
-        let (a = function() { for (var r=0;r<6;++r) ++a; }) {
+        {
+            let a = function() { for (var r=0;r<6;++r) ++a; };
             a();
         }
         props[a] = true;
diff --git a/js/src/jit-test/tests/basic/testBug714650.js b/js/src/jit-test/tests/basic/testBug714650.js
index 9474ea51161..2284faa197a 100644
--- a/js/src/jit-test/tests/basic/testBug714650.js
+++ b/js/src/jit-test/tests/basic/testBug714650.js
@@ -1,4 +1,5 @@
-let ([] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [],
+{ 
+ let [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [],
      [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [],
      [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [],
      [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [],
@@ -30,7 +31,6 @@ let ([] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], []
      [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [],
      [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [],
      [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [],
-     [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [])
-{
+     [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [], [] = [];
     print("ok");
 }
diff --git a/js/src/jit-test/tests/basic/testBug776191.js b/js/src/jit-test/tests/basic/testBug776191.js
index c821cf84c8b..043e50111df 100644
--- a/js/src/jit-test/tests/basic/testBug776191.js
+++ b/js/src/jit-test/tests/basic/testBug776191.js
@@ -1,7 +1,8 @@
 (function() {
-    let(a, b, c) {
+    {
+      let a, b, c;
         ((function() {
-            with({}) let(b) { ((function() { c = 0 })()) }
+            with({}) { { let b; { ((function() { c = 0 })()) } } }
         })())
     }
 })()
diff --git a/js/src/jit-test/tests/basic/testClosureIncrSideExit.js b/js/src/jit-test/tests/basic/testClosureIncrSideExit.js
index 14e8527ebb1..04251e3f364 100644
--- a/js/src/jit-test/tests/basic/testClosureIncrSideExit.js
+++ b/js/src/jit-test/tests/basic/testClosureIncrSideExit.js
@@ -1,16 +1,18 @@
 function testClosureIncrSideExit() {
-    let(f = function (y) {
-        let(ff = function (g) {
+    {
+      let f = function (y) {
+        {
+          let ff = function (g) {
             for each(let h in g) {
                 if (++y > 5) {
                     return 'ddd';
                 }
             }
             return 'qqq';
-        }) {
+        };
             return ff(['', null, '', false, '', '', null]);
         }
-    }) {
+      };
         return f(-1);
     }
 }
diff --git a/js/src/jit-test/tests/basic/testDynamicLookup.js b/js/src/jit-test/tests/basic/testDynamicLookup.js
index 86571ea4720..781c9f8a7aa 100644
--- a/js/src/jit-test/tests/basic/testDynamicLookup.js
+++ b/js/src/jit-test/tests/basic/testDynamicLookup.js
@@ -39,18 +39,12 @@
 (function() { var [x] = [2]; (function() { eval('assertEq(x, 2)') })() })();
 (function() { for (var [x] = [2];;) { return (function() { return assertEq(x, 2); })() } })();
 (function() { for (var [x] = [2];;) { return (function() { return eval('assertEq(x, 2)'); })() } })();
-(function() { let ([x] = [2]) { eval('assertEq(x, 2)') } })();
-(function() { let ([x] = [2]) { (function() { assertEq(x, 2) })() } })();
-(function() { let ([x] = [2]) { (function() { eval('assertEq(x, 2)') })() } })();
 
 (function() { var {y:x} = {y:2}; eval('assertEq(x, 2)') })();
 (function() { var {y:x} = {y:2}; (function() { assertEq(x, 2) })() })();
 (function() { var {y:x} = {y:2}; (function() { eval('assertEq(x, 2)') })() })();
 (function() { for (var {y:x} = {y:2};;) { return (function() { return assertEq(x, 2); })() } })();
 (function() { for (var {y:x} = {y:2};;) { return (function() { return eval('assertEq(x, 2)'); })() } })();
-(function() { let ({y:x} = {y:2}) { eval('assertEq(x, 2)') } })();
-(function() { let ({y:x} = {y:2}) { (function() { assertEq(x, 2) })() } })();
-(function() { let ({y:x} = {y:2}) { (function() { eval('assertEq(x, 2)') })() } })();
 
 (function([x]) { eval('assertEq(x, 2)') })([2]);
 (function([x]) { (function() { assertEq(x, 2) })() })([2]);
diff --git a/js/src/jit-test/tests/basic/testDynamicUsage.js b/js/src/jit-test/tests/basic/testDynamicUsage.js
index ae6a6e4c8c6..65c1f8efc9b 100644
--- a/js/src/jit-test/tests/basic/testDynamicUsage.js
+++ b/js/src/jit-test/tests/basic/testDynamicUsage.js
@@ -37,8 +37,8 @@ assertEq((function(a,x,y) { [x,y] = a; x += y; return (function() eval('x'))() }
 
 assertEq((function() { var [x,y] = [1,2]; x += y; return (function() x)() })(), 3);
 assertEq((function() { var [x,y] = [1,2]; (function() x += y)(); return x })(), 3);
-assertEq((function() { let ([x,y] = [1,2]) { x += y; return (function() x)() } })(), 3);
-assertEq((function() { let ([x,y] = [1,2]) { (function() x += y)(); return x } })(), 3);
+assertEq((function() { { let [x,y] = [1,2]; x += y; return (function() x)() } })(), 3);
+assertEq((function() { { let [x,y] = [1,2]; (function() x += y)(); return x } })(), 3);
 
 assertEq((function([x,y]) { (function() { x += y })(); return x })([1,2]), 3);
 assertEq((function([x,y]) { x += y; return (function() x)() })([1,2]), 3);
@@ -55,18 +55,18 @@ assertEq((function() { try { throw [1,2] } catch([x,y]) { x += y; return (functi
 
 assertEq((function(a) { let [x,y] = a; (function() { x += y })(); return x })([1,2]), 3);
 assertEq((function(a) { let [x,y] = a; x += y; return (function() x)() })([1,2]), 3);
-assertEq((function(a) { let ([x,y] = a) { (function() { x += y })(); return x } })([1,2]), 3);
-assertEq((function(a) { let ([x,y] = a) { x += y; return (function() x)() } })([1,2]), 3);
-assertEq((function(a) { let ([[l, x],[m, y]] = a) { (function() { x += y })(); return x } })([[0,1],[0,2]]), 3);
-assertEq((function(a) { let ([[l, x],[m, y]] = a) { x += y; return (function() x)() } })([[0,1],[0,2]]), 3);
+assertEq((function(a) { { let [x,y] = a; (function() { x += y })(); return x } })([1,2]), 3);
+assertEq((function(a) { { let [x,y] = a; x += y; return (function() x)() } })([1,2]), 3);
+assertEq((function(a) { { let [[l, x],[m, y]] = a; (function() { x += y })(); return x } })([[0,1],[0,2]]), 3);
+assertEq((function(a) { { let [[l, x],[m, y]] = a; x += y; return (function() x)() } })([[0,1],[0,2]]), 3);
 
 assertEq((function() { let x = 3; return (function() { return x })() })(), 3);
 assertEq((function() { let g = function() { return x }; let x = 3; return g() })(), 3);
 
-assertEq((function() { let (x = 3) { return (function() { return x })() } })(), 3);
-assertEq((function() { let (x = 3) { (function() { assertEq(x, 3) })(); return x } })(), 3);
-assertEq((function() { let (x = 2) { x = 3; return (function() { return x })() } })(), 3);
-assertEq((function() { let (x = 1) { let (x = 3) { (function() { assertEq(x,3) })() } return x } })(), 1);
+assertEq((function() { { let x = 3; return (function() { return x })() } })(), 3);
+assertEq((function() { { let x = 3; (function() { assertEq(x, 3) })(); return x } })(), 3);
+assertEq((function() { { let x = 2; x = 3; return (function() { return x })() } })(), 3);
+assertEq((function() { { let x = 1; { let x = 3; (function() { assertEq(x,3) })() } return x } })(), 1);
 
 assertEq((function() { try { throw 3 } catch (e) { (function(){assertEq(e,3)})(); return e } })(), 3);
 assertEq((function() { try { throw 3 } catch (e) { assertEq(e, 3); return (function() e)() } })(), 3);
diff --git a/js/src/jit-test/tests/basic/testGlobalOptimize-2.js b/js/src/jit-test/tests/basic/testGlobalOptimize-2.js
index 53b3bff2859..3aa1db61046 100644
--- a/js/src/jit-test/tests/basic/testGlobalOptimize-2.js
+++ b/js/src/jit-test/tests/basic/testGlobalOptimize-2.js
@@ -1,9 +1,8 @@
 var test;
 {
-  let (a = 5) {
+  let a = 5;
     with ({a: 2}) {
       test = (function () { return a; })();
     }
-  }
 }
 assertEq(test, 2);
diff --git a/js/src/jit-test/tests/basic/testGlobalOptimize-3.js b/js/src/jit-test/tests/basic/testGlobalOptimize-3.js
index 020138b99c1..ef62a708902 100644
--- a/js/src/jit-test/tests/basic/testGlobalOptimize-3.js
+++ b/js/src/jit-test/tests/basic/testGlobalOptimize-3.js
@@ -1,7 +1,8 @@
 var test;
 {
   with ({a: 2}) {
-    let (a = 5) {
+    {
+      let a = 5;
       test = (function () { return a; })();
     }
   }
diff --git a/js/src/jit-test/tests/basic/testGlobalOptimize-5.js b/js/src/jit-test/tests/basic/testGlobalOptimize-5.js
index 20c3babb3db..e0a3aecc2e3 100644
--- a/js/src/jit-test/tests/basic/testGlobalOptimize-5.js
+++ b/js/src/jit-test/tests/basic/testGlobalOptimize-5.js
@@ -1,6 +1,7 @@
 var test;
 function f() {
-  let (a = 5) {
+  {
+    let a = 5;
     with ({a: 2}) {
       test = (function () { return a;} )();
     }
diff --git a/js/src/jit-test/tests/basic/testGlobalOptimize-6.js b/js/src/jit-test/tests/basic/testGlobalOptimize-6.js
index fe3174afbc5..4bc14058e8e 100644
--- a/js/src/jit-test/tests/basic/testGlobalOptimize-6.js
+++ b/js/src/jit-test/tests/basic/testGlobalOptimize-6.js
@@ -1,7 +1,8 @@
 var test;
 function f() {
   with ({a: 2}) {
-    let (a = 5) {
+    {
+      let a = 5;
       test = (function () { return a; })();
     }
   }
diff --git a/js/src/jit-test/tests/basic/testLet.js b/js/src/jit-test/tests/basic/testLet.js
index aaa78af6397..a79c8a521e2 100644
--- a/js/src/jit-test/tests/basic/testLet.js
+++ b/js/src/jit-test/tests/basic/testLet.js
@@ -68,99 +68,6 @@ function isReferenceError(str)
     assertEq(caught, true);
 }
 
-// let expr
-isParseError('return let (y) x;');
-isParseError('return let (x) "" + x;', 'unicorns', 'undefined');
-isParseError('return let (y = x) (y++, "" + y);', 'unicorns', 'NaN');
-isParseError('return let (y = 1) (y = x, y);');
-isParseError('return let ([] = x) x;');
-isParseError('return let (x = {a: x}) x.a;');
-isParseError('return let ({a: x} = {a: x}) x;');
-isParseError('return let ([x] = [x]) x;');
-isParseError('return let ({0: x} = [x]) x;');
-isParseError('return let ({0: []} = [[]]) x;');
-isParseError('return let ([, ] = x) x;');
-isParseError('return let ([, , , , ] = x) x;');
-isParseError('return let (x = x) x;');
-isParseError('return let (x = eval("x")) x;');
-isParseError('return let (x = (let (x = x + 1) x) + 1) x;', 1, 3);
-isParseError('return let (x = (let (x = eval("x") + 1) eval("x")) + 1) eval("x");', 1, 3);
-isParseError('return let (x = x + 1, y = x) y;');
-isParseError('return let (x = x + 1, [] = x, /*[[, , ]] = x, */y = x) y;');
-isParseError('return let ([{a: x}] = x, [, {b: y}] = x) let (x = x + 1, y = y + 2) x + y;', [{a:"p"},{b:"p"}], "p1p2");
-isParseError('return let ([] = []) x;');
-isParseError('return let ([] = [x]) x;');
-isParseError('return let ([a] = (1, [x])) a;');
-isParseError('return let ([a] = (1, x, 1, x)) a;', ['ponies']);
-isParseError('return let ([x] = [x]) x;');
-isParseError('return let ([[a, [b, c]]] = [[x, []]]) a;');
-isParseError('return let ([x, y] = [x, x + 1]) x + y;', 1, 3);
-isParseError('return let ([x, y, z] = [x, x + 1, x + 2]) x + y + z;', 1, 6);
-isParseError('return let ([[x]] = [[x]]) x;');
-isParseError('return let ([x, y] = [x, x + 1]) x;');
-isParseError('return let ([x, [y, z]] = [x, x + 1]) x;');
-isParseError('return let ([{x: [x]}, {y1: y, z1: z}] = [x, x + 1]) x;',{x:['ponies']});
-isParseError('return let (x = (3, x)) x;');
-isParseError('return let (x = x + "s") x;', 'ponie');
-isParseError('return let ([x] = (3, [x])) x;');
-isParseError('return let (y = x) function () {return eval("y");}();');
-isParseError('return let (y = x) (eval("var y = 2"), y);', 'ponies', 2);
-isParseError('"use strict";return let (y = x) (eval("var y = 2"), y);');
-isParseError('this.y = x;return let (y = 1) this.eval("y");');
-isParseError('try {let (x = x) eval("throw x");} catch (e) {return e;}');
-isParseError('try {return let (x = eval("throw x")) x;} catch (e) {return e;}');
-isParseError('let (x = 1, x = 2) x');
-isParseError('let ([x, y] = a, {a:x} = b) x');
-isParseError('let ([x, y, x] = a) x');
-isParseError('let ([x, [y, [x]]] = a) x');
-isParseError('let (x = function() { return x}) x()return x;');
-isParseError('(let (x = function() { return x}) x())return x;');
-
-// let block
-test('let (y) {return x;}');
-test('let (y = x) {y++;return "" + y;}', 'unicorns', 'NaN');
-test('let (y = 1) {y = x;return y;}');
-test('let (x) {return "" + x;}', 'unicorns', 'undefined');
-test('let ([] = x) {return x;}');
-test('let (x) {}return x;');
-test('let (x = {a: x}) {return x.a;}');
-test('let ({a: x} = {a: x}) {return x;}');
-test('let ([x] = [x]) {return x;}');
-test('let ({0: x} = [x]) {return x;}');
-test('let ({0: []} = [[]]) {return x;}');
-test('let ([, ] = x) {return x;}');
-test('let ([, , , , ] = x) {return x;}');
-test('let (x = x) {return x;}');
-test('let (x = eval("x")) {return x;}');
-isParseError('let (x = (let (x = x + 1) x) + 1) {return x;}', 1, 3);
-isParseError('let (x = (let (x = eval("x") + 1) eval("x")) + 1) {return eval("x");}', 1, 3);
-test('let (x = x + 1, y = x) {return y;}');
-test('let (x = x + 1, [] = x, [[, , ]] = x, y = x) {return y;}');
-test('let ([{a: x}] = x, [, {b: y}] = x) {let (x = x + 1, y = y + 2) {return x + y;}}', [{a:"p"},{b:"p"}], "p1p2");
-test('let ([] = []) {return x;}');
-test('let ([] = [x]) {return x;}');
-test('let ([a] = (1, [x])) {return a;}');
-test('let ([a] = (1, x, 1, x)) {return a;}', ['ponies']);
-test('let ([x] = [x]) {return x;}');
-test('let ([[a, [b, c]]] = [[x, []]]) {return a;}');
-test('let ([x, y] = [x, x + 1]) {return x + y;}', 1, 3);
-test('let ([x, y, z] = [x, x + 1, x + 2]) {return x + y + z;}', 1, 6);
-test('let ([[x]] = [[x]]) {return x;}');
-test('let ([x, y] = [x, x + 1]) {return x;}');
-test('let ([x, [y, z]] = [x, x + 1]) {return x;}');
-test('let ([{x: [x]}, {y1: y, z1: z}] = [x, x + 1]) {return x;}',{x:['ponies']});
-test('let (y = x[1]) {let (x = x[0]) {try {let (y = "unicorns") {throw y;}} catch (e) {return x + y;}}}', ['pon','ies']);
-isParseError('let (x = x) {try {let (x = "unicorns") eval("throw x");} catch (e) {return x;}}');
-test('let (y = x) {return function () {return eval("y");}();}');
-test('return eval("let (y = x) {y;}");');
-isRuntimeParseError('let (y = x) {eval("var y = 2");return y;}', 'ponies');
-test('"use strict";let (y = x) {eval("var y = 2");return y;}');
-test('this.y = x;let (y = 1) {return this.eval("y");}');
-isParseError('let (x = 1, x = 2) {x}');
-isParseError('let ([x, y] = a, {a:x} = b) {x}');
-isParseError('let ([x, y, x] = a) {x}');
-isParseError('let ([x, [y, [x]]] = a) {x}');
-
 // var declarations
 test('var y;return x;');
 test('var y = x;return x;');
@@ -170,8 +77,6 @@ test('var [, , , , ] = x;return x;');
 test('var x = x;return x;');
 test('var y = y;return "" + y;', 'unicorns', 'undefined');
 test('var x = eval("x");return x;');
-isParseError('var x = (let (x = x + 1) x) + 1;return x;', 1, 3);
-isParseError('var x = (let (x = eval("x") + 1) eval("x")) + 1;return eval("x");', 1, 3);
 test('var X = x + 1, y = x;return y;');
 test('var X = x + 1, [] = X, [[, , ]] = X, y = x;return y;');
 test('var [{a: X}] = x, [, {b: y}] = x;var X = X + 1, y = y + 2;return X + y;', [{a:"p"},{b:"p"}], "p1p2");
@@ -198,8 +103,6 @@ test('if (x) {let y = x;return x;}');
 test('if (x) {let [] = x;return x;}');
 test('if (x) {let [, ] = x;return x;}');
 test('if (x) {let [, , , , ] = x;return x;}');
-isParseError('if (x) {let y = (let (x = x + 1) x) + 1;return y;}', 1, 3);
-isParseError('if (x) {let y = (let (x = eval("x") + 1) eval("x")) + 1;return eval("y");}', 1, 3);
 test('if (x) {let X = x + 1, y = x;return y;}');
 test('if (x) {let X = x + 1, [] = X, [[, , ]] = X, y = x;return y;}');
 test('if (x) {let [{a: X}] = x, [, {b: Y}] = x;var XX = X + 1, YY = Y + 2;return XX + YY;}', [{a:"p"},{b:"p"}], "p1p2");
@@ -215,14 +118,7 @@ test('if (x) {let [X, y] = [x, x + 1];return X;}');
 test('if (x) {let [X, [y, z]] = [x, x + 1];return X;}');
 test('if (x) {let [{x: [X]}, {y1: y, z1: z}] = [x, x + 1];return X;}',{x:['ponies']});
 test('if (x) {let y = x;try {let x = 1;throw 2;} catch (e) {return y;}}');
-test('let (y, [] = x) {}try {let a = b(), b;} catch (e) {return x;}');
 test('try {let x = 1;throw 2;} catch (e) {return x;}');
-test('let (y = x) {let x;return y;}');
-test('let (y = x) {let x = y;return x;}');
-test('let ([y, z] = x) {let a = x, b = y;return a;}');
-test('let ([y, z] = x, a = x, [] = x) {let b = x, c = y;return a;}');
-test('function f() {return unicorns;}try {let (x = 1) {let a, b;f();}} catch (e) {return x;}');
-test('function f() {return unicorns;}try {let (x = 1) {let a, b;}f();} catch (e) {return x;}');
 test('x.foo;{let y = x;return y;}');
 test('x.foo;if (x) {x.bar;let y = x;return y;}');
 test('if (x) {let y = x;return function () {return eval("y");}();}');
@@ -232,19 +128,12 @@ test('"use strict";if (x) {let y = x;eval("var y = 2");return y;}');
 test('"use strict";if (x) {let y = x;eval("let y = 2");return y;}');
 test('"use strict";if (x) {let y = 1;return eval("let y = x;y;");}');
 test('this.y = x;if (x) {let y = 1;return this.eval("y");}');
-isParseError('if (x) {let (x = 1, x = 2) {x}}');
-isParseError('if (x) {let ([x, y] = a, {a:x} = b) {x}}');
-isParseError('if (x) {let ([x, y, x] = a) {x}}');
-isParseError('if (x) {let ([x, [y, [x]]] = a) {x}}');
-isParseError('let ([x, y] = x) {let x;}');
 
 // for(;;)
 test('for (;;) {return x;}');
 test('for (let y = 1;;) {return x;}');
 test('for (let y = 1;; ++y) {return x;}');
 test('for (let y = 1; ++y;) {return x;}');
-isParseError('for (let (x = 1) x; x != 1; ++x) {return x;}');
-isParseError('for (let (x = 1, [{a: b, c: d}] = [{a: 1, c: 2}]) x; x != 1; ++x) {return x;}');
 test('for (let [[a, [b, c]]] = [[x, []]];;) {return a;}');
 test('var sum = 0;for (let y = x; y < 4; ++y) {sum += y;}return sum;', 1, 6);
 test('var sum = 0;for (let x = x, y = 10; x < 4; ++x) {sum += x;}return sum;', 1, 6);
@@ -280,7 +169,6 @@ isParseError('for (let [x, [y, [x]]] = a;;) {}');
 test('for (let i in x) {return x;}');
 test('for (let i in x) {let y;return x;}');
 test('for each (let [a, b] in x) {let y;return x;}');
-test('for (let i in x) {let (i = x) {return i;}}');
 test('for (let i in x) {let i = x;return i;}');
 test('for each (let [x, y] in x) {return x + y;}', [['ponies', '']]);
 test('for each (let [{0: x, 1: y}, z] in x) {return x + y + z;}', [[['po','nies'], '']]);
@@ -291,7 +179,6 @@ test('for each (let {x: y, y: x} in [{x: x, y: x}]) {return y;}');
 test('for (let x in eval("x")) {return x;}', {ponies:true});
 test('for (let x in x) {return eval("x");}', {ponies:true});
 test('for (let x in eval("x")) {return eval("x");}', {ponies:true});
-isParseError('for ((let (x = {y: true}) x).y in eval("x")) {return eval("x");}');
 test('for (let i in x) {break;}return x;');
 test('for (let i in x) {break;}return eval("x");');
 test('for (let x in x) {break;}return x;');
@@ -320,7 +207,6 @@ test('try {return [eval("throw i") for (i in x)][0];} catch (e) {return e;}', {p
 // don't forget about switch craziness
 test('var y = 3;switch (function () {return eval("y");}()) {case 3:let y;return x;default:;}');
 test('switch (x) {case 3:let y;return 3;case 4:let z;return 4;default:return x;}');
-test('switch (x) {case 3:default:let y;let (y = x) {return y;}}');
 isParseError('switch (x) {case 3:let y;return 3;case 4:let y;return 4;default:;}');
 
 // TDZ checks
diff --git a/js/src/jit-test/tests/basic/testLetOverridingArgs.js b/js/src/jit-test/tests/basic/testLetOverridingArgs.js
index 0fbc31b4a5e..fbebe7a2fc2 100644
--- a/js/src/jit-test/tests/basic/testLetOverridingArgs.js
+++ b/js/src/jit-test/tests/basic/testLetOverridingArgs.js
@@ -1,5 +1,5 @@
-function f1() { let (arguments = 42) { return arguments } }
+function f1() { { let arguments = 42; return arguments } }
 assertEq(f1(), 42);
 
-function f2() { let (arguments) { return arguments } }
+function f2() { { let arguments; return arguments } }
 assertEq(f2(), undefined);
diff --git a/js/src/jit-test/tests/basic/testNonStubGetter.js b/js/src/jit-test/tests/basic/testNonStubGetter.js
index 4d6ec6430ef..58a698eb4fe 100644
--- a/js/src/jit-test/tests/basic/testNonStubGetter.js
+++ b/js/src/jit-test/tests/basic/testNonStubGetter.js
@@ -1,5 +1,5 @@
 function testNonStubGetter() {
-    let ([] = []) { (this.watch("x", function(p, o, n) { return /a/g.exec(p, o, n); })); };
+    { let [] = []; (this.watch("x", function(p, o, n) { return /a/g.exec(p, o, n); })); };
     (function () { (eval("(function(){for each (x in [1, 2, 2]);});"))(); })();
     this.unwatch("x");
     return "ok";
diff --git a/js/src/jit-test/tests/basic/testReplaceWithLambda.js b/js/src/jit-test/tests/basic/testReplaceWithLambda.js
index e78feb7afc3..9aad5ef98b4 100644
--- a/js/src/jit-test/tests/basic/testReplaceWithLambda.js
+++ b/js/src/jit-test/tests/basic/testReplaceWithLambda.js
@@ -7,7 +7,8 @@
     assertEq("abc".replace(/a|b/g, function(a) { return b[a] }), 'ABc');
 })();
 (function() {
-    let (b = {a:'A', b:'B' }) {
+    {
+        let b = {a:'A', b:'B' };
         assertEq("abc".replace(/a|b/g, function(a) { return b[a] }), 'ABc');
     }
 })();
@@ -18,7 +19,8 @@
     })();
 })();
 (function() {
-    let (b = {a:'A', b:'B' }) {
+    {
+        let b = {a:'A', b:'B' };
         (function () {
             assertEq("abc".replace(/a|b/g, function(a) { return b[a] }), 'ABc');
         })();
diff --git a/js/src/jit-test/tests/basic/testScriptCloning.js b/js/src/jit-test/tests/basic/testScriptCloning.js
index 18835f56cfc..4099acfb96d 100644
--- a/js/src/jit-test/tests/basic/testScriptCloning.js
+++ b/js/src/jit-test/tests/basic/testScriptCloning.js
@@ -3,10 +3,10 @@ var g = newGlobal();
 g.f = new Function('return function(x) { return x };');
 assertEq(g.eval("clone(f)()(9)"), 9);
 
-g.f = new Function('return function(x) { let(y = x+1) { return y } };');
+g.f = new Function('return function(x) { { let y = x+1; return y } };');
 assertEq(g.eval("clone(f)()(9)"), 10);
 
-g.f = new Function('return function(x) { let(y = x, z = 1) { return y+z } };');
+g.f = new Function('return function(x) { { let y = x, z = 1; return y+z } };');
 assertEq(g.eval("clone(f)()(9)"), 10);
 
 g.f = new Function('return function(x) { return x.search(/ponies/) };');
diff --git a/js/src/jit-test/tests/basic/testStaticEvalScope.js b/js/src/jit-test/tests/basic/testStaticEvalScope.js
index 980b0cc830f..6850f3bf4c8 100644
--- a/js/src/jit-test/tests/basic/testStaticEvalScope.js
+++ b/js/src/jit-test/tests/basic/testStaticEvalScope.js
@@ -1,3 +1,3 @@
 // Test that static eval scopes don't mess with statement nested scope logic in
 // the frontend.
-eval("if (true) { let(y){} } else {}")
+eval("if (true) { { let y; } } else {}")
diff --git a/js/src/jit-test/tests/bug1213574.js b/js/src/jit-test/tests/bug1213574.js
index 8761f8b0733..6d94c5aa049 100644
--- a/js/src/jit-test/tests/bug1213574.js
+++ b/js/src/jit-test/tests/bug1213574.js
@@ -2,7 +2,7 @@ if (helperThreadCount() === 0)
     quit(0);
 
 var lfGlobal = newGlobal();
-lfGlobal.offThreadCompileScript(`let (x) { throw 42; }`);
+lfGlobal.offThreadCompileScript(`{ let x; throw 42; }`);
 try {
     lfGlobal.runOffThreadScript();
 } catch (e) {
diff --git a/js/src/jit-test/tests/closures/bug496922.js b/js/src/jit-test/tests/closures/bug496922.js
index 7b351b19afa..a0aeca1d268 100644
--- a/js/src/jit-test/tests/closures/bug496922.js
+++ b/js/src/jit-test/tests/closures/bug496922.js
@@ -2,8 +2,8 @@ actual = '';
 expected = '0,0,1,1,2,2,3,3,';
 
 v = 0
-let(
-f = function() {
+{
+let f = function() {
     for (let x = 0; x < 4; ++x) {
         v >> x;
         (function() {
@@ -12,7 +12,8 @@ f = function() {
             }
         })()
     }
-}) { (function() {})()
+};
+(function() {})()
     f(v)
 }
 
diff --git a/js/src/jit-test/tests/closures/bug540131.js b/js/src/jit-test/tests/closures/bug540131.js
index 2a46ae8418f..4584ac350a5 100644
--- a/js/src/jit-test/tests/closures/bug540131.js
+++ b/js/src/jit-test/tests/closures/bug540131.js
@@ -1,5 +1,5 @@
 try {
  (function() {
-   let(x = (eval("for(y in[0,0,0,0]){}"))) {}
+   { let x = (eval("for(y in[0,0,0,0]){}")); }
  })()
 } catch(e) {}
diff --git a/js/src/jit-test/tests/closures/flat-closure-2.js b/js/src/jit-test/tests/closures/flat-closure-2.js
index 41514d993b9..ae1043097e3 100644
--- a/js/src/jit-test/tests/closures/flat-closure-2.js
+++ b/js/src/jit-test/tests/closures/flat-closure-2.js
@@ -1,11 +1,10 @@
 actual = '';
 expected = 'nocrash,';
 
-let (z = {}) {
-    for (var i = 0; i < 4; ++i) {
-        for each (var e in [{}, 1, {}]) {
-            +(function () z)();
-        }
+let z = {};
+for (var i = 0; i < 4; ++i) {
+    for each (var e in [{}, 1, {}]) {
+        +(function () z)();
     }
 }
 
diff --git a/js/src/jit-test/tests/closures/flat-closure-7.js b/js/src/jit-test/tests/closures/flat-closure-7.js
index 0cf873ad111..8f653a52f45 100644
--- a/js/src/jit-test/tests/closures/flat-closure-7.js
+++ b/js/src/jit-test/tests/closures/flat-closure-7.js
@@ -4,10 +4,9 @@ expected = '0 0 0 0 0 0 0 0 0,';
     var o = [];
     for (var a = 0; a < 9; ++a) {
         var unused = 0;
-        let (zero = 0) {
-            for (var ee = 0; ee < 1; ++ee) {
-                o.push((function () zero)());
-            }
+        let zero = 0;
+        for (var ee = 0; ee < 1; ++ee) {
+          o.push((function () zero)());
         }
     }
     appendToActual(o.join(" "));
diff --git a/js/src/jit-test/tests/closures/incr-exit-2.js b/js/src/jit-test/tests/closures/incr-exit-2.js
index d87ab968bcb..643f0ec6fb5 100644
--- a/js/src/jit-test/tests/closures/incr-exit-2.js
+++ b/js/src/jit-test/tests/closures/incr-exit-2.js
@@ -2,17 +2,17 @@ actual = '';
 expected = '-3,';
 
 v = 0
-let(f = function (y) {
-    let(f = function (g) {
+{ let f = function (y) {
+    { let f = function (g) {
         for each(let h in g) {
             if (++y > 2) {
                 appendToActual(h)
             }
         }
-    }) {
+    };
         f([(--y), false, true, (--y), false, (--y)])
     }
-}) {
+};
     f(v)
 }
 
diff --git a/js/src/jit-test/tests/closures/incr-exit-3.js b/js/src/jit-test/tests/closures/incr-exit-3.js
index e15212dc609..c91992a2d02 100644
--- a/js/src/jit-test/tests/closures/incr-exit-3.js
+++ b/js/src/jit-test/tests/closures/incr-exit-3.js
@@ -2,25 +2,25 @@ actual = '';
 expected = 'foo4,foo4,';
 
 v = 0
-let(f = function (y) {
-    let(f = function (y) {
-        let(f = function (g) {
+{ let f = function (y) {
+    { let f = function (y) {
+        { let f = function (g) {
             for (h in g) {
                 if (++y > 3) {
                     appendToActual('foo' + y)
                 }
             }
-        }) {
+        };
             f([y
             for (b in [1, []])]);
             f(['', false])
         }
         v = String
-    }) {
+    };
         f(y)
         f(y)
     }
-}) {
+};
     f(v)
 }
 
diff --git a/js/src/jit-test/tests/closures/incr-exit.js b/js/src/jit-test/tests/closures/incr-exit.js
index 6eb303ab528..34888b52527 100644
--- a/js/src/jit-test/tests/closures/incr-exit.js
+++ b/js/src/jit-test/tests/closures/incr-exit.js
@@ -2,17 +2,17 @@ actual = '';
 expected = 'ddd,';
 
 // Bug 508187
-let(f = function (y) {
-    let(ff = function (g) {
+{ let f = function (y) {
+    { let ff = function (g) {
         for each(let h in g) {
             if (++y > 5) {
 	        appendToActual('ddd')
             }
         }
-    }) {
+    };
       ff(['', null, '', false, '', '', null])
     }
-}) {
+};
     f(-1)
 }
 
diff --git a/js/src/jit-test/tests/closures/lambda-light.js b/js/src/jit-test/tests/closures/lambda-light.js
index b56893b2edf..933da605ee2 100644
--- a/js/src/jit-test/tests/closures/lambda-light.js
+++ b/js/src/jit-test/tests/closures/lambda-light.js
@@ -2,10 +2,11 @@ actual = '';
 expected = '10,';
 
 function f(x) {
-  let (x = 10) {
+  {
+    let x2 = 10;
     for (var i = 0; i < 5; ++i) {
       var g = function () {
-	appendToActual(x);
+	appendToActual(x2);
       };
     }
     g();
diff --git a/js/src/jit-test/tests/closures/t020.js b/js/src/jit-test/tests/closures/t020.js
index a1b8f03131f..30c8b463df8 100644
--- a/js/src/jit-test/tests/closures/t020.js
+++ b/js/src/jit-test/tests/closures/t020.js
@@ -1,7 +1,7 @@
 actual = '';
 expected = '0,0,1,1,2,2,3,3,';
 
-let(f = function() {
+{ let f = function() {
     for (let x = 0; x < 4; ++x) {
       (function() {
 	for (let y = 0; y < 2; ++y) {
@@ -9,7 +9,7 @@ let(f = function() {
 	}
       })()
 	}
-}) { 
+};
     f(0)
 }
 
diff --git a/js/src/jit-test/tests/debug/Environment-callee-01.js b/js/src/jit-test/tests/debug/Environment-callee-01.js
index b3d84ec70a9..424e9164ab6 100644
--- a/js/src/jit-test/tests/debug/Environment-callee-01.js
+++ b/js/src/jit-test/tests/debug/Environment-callee-01.js
@@ -21,7 +21,7 @@ function check(code, expectedType, expectedCallee) {
 
 check('debugger;', 'declarative', null);
 check('with({}) { debugger; };', 'with', null);
-check('let (x=1) { debugger; };', 'declarative', null);
+check('{ let x=1; debugger; };', 'declarative', null);
 
 g.eval('function f() { debugger; }');
 check('f()', 'declarative', gw.makeDebuggeeValue(g.f));
@@ -41,7 +41,7 @@ check('eval("debugger");', 'declarative', null);
 g.eval('function m() { debugger; yield true; }');
 check('m().next();', 'declarative', gw.makeDebuggeeValue(g.m));
 
-g.eval('function n() { let (x = 1) { debugger; } }');
+g.eval('function n() { { let x = 1; debugger; } }');
 check('n()', 'declarative', null);
 
 g.eval('function* o() { debugger; yield true; }');
diff --git a/js/src/jit-test/tests/debug/Environment-getVariable-03.js b/js/src/jit-test/tests/debug/Environment-getVariable-03.js
index d58d399cf36..b47fe65c145 100644
--- a/js/src/jit-test/tests/debug/Environment-getVariable-03.js
+++ b/js/src/jit-test/tests/debug/Environment-getVariable-03.js
@@ -17,6 +17,5 @@ g.eval("function f() {\n" +
        "        }\n" +
        "}\n");
 g.f();
-g.eval("let (x = 'c') { debugger; }");
 g.eval("{ let x = 'd'; debugger; }");
-assertEq(log, 'a0bcd');
+assertEq(log, 'a0bd');
diff --git a/js/src/jit-test/tests/debug/Environment-getVariable-12.js b/js/src/jit-test/tests/debug/Environment-getVariable-12.js
index b6852bb6fa0..ac6f5efb8de 100644
--- a/js/src/jit-test/tests/debug/Environment-getVariable-12.js
+++ b/js/src/jit-test/tests/debug/Environment-getVariable-12.js
@@ -10,7 +10,7 @@ dbg.onDebuggerStatement = function (frame) {
 
 g.eval("var g;" +
        "function f(x) {" +
-       "  let (y = x) {" +
+       "  { let y = x; " +
        "    if (x)" +
        "      g = function() { eval('debugger') };" +
        "    else" +
@@ -29,9 +29,9 @@ dbg.onDebuggerStatement = function (frame) {
 };
 
 g.eval("var g;" +
-       "let (y = 1) {" +
+       "{ let y = 1; " +
        "  g = function () { debugger; };" +
-       "  let (z = 2) {" +
+       "  { let z = 2; " +
        "    g();" +
        "  }"+
        "}");
@@ -49,8 +49,8 @@ dbg.onDebuggerStatement = function (frame) {
 g.eval("var g;" +
        "function h() { debugger };" +
        "for (var x of [true, false]) {" +
-       "  let (y = x) {" +
-       "    let (z = x) {" +
+       "  { let y = x; " +
+       "    { let z = x; " +
        "      if (x)" +
        "        g = function () { print(z); h() };" +
        "      else" +
diff --git a/js/src/jit-test/tests/debug/Environment-identity-03.js b/js/src/jit-test/tests/debug/Environment-identity-03.js
index 3f7e843c187..d4fc3269f70 100644
--- a/js/src/jit-test/tests/debug/Environment-identity-03.js
+++ b/js/src/jit-test/tests/debug/Environment-identity-03.js
@@ -54,7 +54,7 @@ function test(sharedName, expectedHits, code) {
 test("q", 2, "let q = function (a) { h(); }; q(1); q(2);");
 test("a", 2, "q = function (a) { (function (b) { h(); a = b; })(2); h(); }; q(1);");
 test("a", 2, "q = function (a) { h(); return function (b) { h(); a = b; }; }; q(1)(2);");
-test("n", 3, "q = function (n) { for (var i = 0; i < n; i++) { let (j = i) { h(); } } }; q(3);");
+test("n", 3, "q = function (n) { for (var i = 0; i < n; i++) { { let j = i; h(); } } }; q(3);");
 
 // A function with long dynamic and static chains.
 var N = 80;
diff --git a/js/src/jit-test/tests/debug/Environment-setVariable-07.js b/js/src/jit-test/tests/debug/Environment-setVariable-07.js
index cce35e58dc0..5e3cdd17787 100644
--- a/js/src/jit-test/tests/debug/Environment-setVariable-07.js
+++ b/js/src/jit-test/tests/debug/Environment-setVariable-07.js
@@ -12,4 +12,3 @@ function test(code, val) {
 
 test("let a = 1; debugger; return a;", "xyzzy");
 test("{ let a = 1; debugger; return a; }", "plugh");
-test("let (a = 1) { debugger; return a; }", "wcgr");
diff --git a/js/src/jit-test/tests/debug/Environment-type-01.js b/js/src/jit-test/tests/debug/Environment-type-01.js
index 3085163c29f..aa3529e0178 100644
--- a/js/src/jit-test/tests/debug/Environment-type-01.js
+++ b/js/src/jit-test/tests/debug/Environment-type-01.js
@@ -15,7 +15,7 @@ test("(function (s) { h(); })();", 'declarative');
 test("{let x = 1, y = 2; h();}", 'declarative');
 test("with({x: 1, y: 2}) h();", 'with');
 test("(function (s) { with ({x: 1, y: 2}) h(); })();", 'with');
-test("let (x = 1) { h(); }", 'declarative');
+test("{ let x = 1; h(); }", 'declarative');
 test("for (let x = 0; x < 1; x++) h();", 'declarative');
 test("for (let x in h()) ;", 'declarative');
 test("for (let x in {a:1}) h();", 'declarative');
diff --git a/js/src/jit-test/tests/debug/Environment-variables.js b/js/src/jit-test/tests/debug/Environment-variables.js
index 22895200a9e..dac58b2fbaa 100644
--- a/js/src/jit-test/tests/debug/Environment-variables.js
+++ b/js/src/jit-test/tests/debug/Environment-variables.js
@@ -12,7 +12,6 @@ var cases = [
     // let, catch, and comprehension bindings
     "let x = VAL; @@",
     "{ let x = VAL; @@ }",
-    "let (x = VAL) { @@ }",
     "try { throw VAL; } catch (x) { @@ }",
     "try { throw VAL; } catch (x) { @@ }",
     "for (let x of [VAL]) { @@ }",
@@ -80,7 +79,7 @@ for (var s of cases) {
     test(s, "debugMe(); assertEq(x, 'ok');");
 
     // Test triggering the debugger from a scope nested in x's scope.
-    test(s, "let (y = 'irrelevant') { (function (z) { let (zz = y) { debugger; }})(); } assertEq(x, 'ok');"),
+    test(s, "{ let y = 'irrelevant'; (function (z) { { let zz = y; debugger; } })(); } assertEq(x, 'ok');"),
 
     // Test closing over the variable and triggering the debugger later, after
     // leaving the variable's scope.
diff --git a/js/src/jit-test/tests/debug/Frame-eval-14.js b/js/src/jit-test/tests/debug/Frame-eval-14.js
index 33ad1dc36a9..b2e8abd661d 100644
--- a/js/src/jit-test/tests/debug/Frame-eval-14.js
+++ b/js/src/jit-test/tests/debug/Frame-eval-14.js
@@ -3,7 +3,7 @@
 
 var g = newGlobal();
 g.eval("function h() { debugger }");
-g.eval("function f() { let (x = 1, y) { (function() { y = 0 })(); h() } }");
+g.eval("function f() { { let x = 1, y; (function() { y = 0 })(); h() } }");
 g.eval("var surprise = null");
 
 var dbg = new Debugger(g);
diff --git a/js/src/jit-test/tests/debug/Frame-evalWithBindings-01.js b/js/src/jit-test/tests/debug/Frame-evalWithBindings-01.js
index 0ebc93392fe..e802d9d27b8 100644
--- a/js/src/jit-test/tests/debug/Frame-evalWithBindings-01.js
+++ b/js/src/jit-test/tests/debug/Frame-evalWithBindings-01.js
@@ -30,6 +30,6 @@ g.f();
 g.eval("with ({y: 3}) { debugger; }");
 
 // shadowing
-g.eval("let (x = 50, y = 3) { debugger; }");
+g.eval("{ let x = 50, y = 3; debugger; }");
 
 assertEq(hits, 6);
diff --git a/js/src/jit-test/tests/debug/bug1188334.js b/js/src/jit-test/tests/debug/bug1188334.js
index 0a3e98c8a63..a5c0a77c431 100644
--- a/js/src/jit-test/tests/debug/bug1188334.js
+++ b/js/src/jit-test/tests/debug/bug1188334.js
@@ -8,7 +8,8 @@ var evalInFrame = (function (global) {
   };
 })(this);
 function f() {
-    let ({} = "xxx") {
+    {
+        let {} = "xxx";
         yield evalInFrame(0, "x");
     }
 }
diff --git a/js/src/jit-test/tests/for-of/syntax-2.js b/js/src/jit-test/tests/for-of/syntax-2.js
index 2f320408b09..2241a392143 100644
--- a/js/src/jit-test/tests/for-of/syntax-2.js
+++ b/js/src/jit-test/tests/for-of/syntax-2.js
@@ -4,6 +4,4 @@ var of;
 
 Function("var of;");
 
-let (of = 12) {}
-
 function of(of) {}
diff --git a/js/src/jit-test/tests/gc/jsscript-mark-children.js b/js/src/jit-test/tests/gc/jsscript-mark-children.js
index 449212a7edc..c74a19c0f37 100644
--- a/js/src/jit-test/tests/gc/jsscript-mark-children.js
+++ b/js/src/jit-test/tests/gc/jsscript-mark-children.js
@@ -8,17 +8,17 @@
 let t = 0;
 gczeal(2,1);
 eval("\
-let x = 3, y = 4;\
-let (x = x+0, y = 12) { t += (x + y); }  \
-let (x = x+1, y = 12) { t += (x + y); }  \
-let (x = x+2, y = 12) { t += (x + y); }  \
-let (x = x+3, y = 12) { t += (x + y); }  \
-let (x = x+4, y = 12) { t += (x + y); }  \
-let (x = x+5, y = 12) { t += (x + y); }  \
-let (x = x+6, y = 12) { t += (x + y); }  \
-let (x = x+7, y = 12) { t += (x + y); }  \
-let (x = x+8, y = 12) { t += (x + y); }  \
-let (x = x+9, y = 12) { t += (x + y); }  \
-t += (x + y);\
+let x0 = 3, y = 4;\
+{ let x = x0+0, y = 12; t += (x + y); }  \
+{ let x = x0+1, y = 12; t += (x + y); }  \
+{ let x = x0+2, y = 12; t += (x + y); }  \
+{ let x = x0+3, y = 12; t += (x + y); }  \
+{ let x = x0+4, y = 12; t += (x + y); }  \
+{ let x = x0+5, y = 12; t += (x + y); }  \
+{ let x = x0+6, y = 12; t += (x + y); }  \
+{ let x = x0+7, y = 12; t += (x + y); }  \
+{ let x = x0+8, y = 12; t += (x + y); }  \
+{ let x = x0+9, y = 12; t += (x + y); }  \
+t += (x0 + y);\
 assertEq(t, 202);\
 ");
diff --git a/js/src/jit-test/tests/jaeger/bug549521.js b/js/src/jit-test/tests/jaeger/bug549521.js
index c92b440b5fc..f7eeee8faeb 100644
--- a/js/src/jit-test/tests/jaeger/bug549521.js
+++ b/js/src/jit-test/tests/jaeger/bug549521.js
@@ -1,7 +1,8 @@
 function f(y) {
     if (y)
         return;
-    let(x) {
+    {
+        let x;
         for (;;) {}
     }
 }
diff --git a/js/src/jit-test/tests/jaeger/bug555922.js b/js/src/jit-test/tests/jaeger/bug555922.js
index b104035cf22..190e6bbb01c 100644
--- a/js/src/jit-test/tests/jaeger/bug555922.js
+++ b/js/src/jit-test/tests/jaeger/bug555922.js
@@ -1,7 +1,8 @@
 enableNoSuchMethod();
 
 (function() {
-  let(z) {
+  {
+    let z;
     for each(b in [{}]) { ({
         get __noSuchMethod__() { return Function }
       }).w()
diff --git a/js/src/jit-test/tests/jaeger/bug582897.js b/js/src/jit-test/tests/jaeger/bug582897.js
index ef846ceb6e9..0c8dbc9b08b 100644
--- a/js/src/jit-test/tests/jaeger/bug582897.js
+++ b/js/src/jit-test/tests/jaeger/bug582897.js
@@ -1,4 +1,5 @@
-let(x) {
+{
+    let x;
     x + x--
 }
 
diff --git a/js/src/jit-test/tests/jaeger/bug582898.js b/js/src/jit-test/tests/jaeger/bug582898.js
index 38080ef139c..7296b3d6e7e 100644
--- a/js/src/jit-test/tests/jaeger/bug582898.js
+++ b/js/src/jit-test/tests/jaeger/bug582898.js
@@ -1,4 +1,5 @@
-let(x = "") {
+{
+    let x = "";
     x++
     assertEq(x, 1);
 }
diff --git a/js/src/jit-test/tests/jaeger/chunk/bug712265.js b/js/src/jit-test/tests/jaeger/chunk/bug712265.js
deleted file mode 100644
index 06de921f00f..00000000000
--- a/js/src/jit-test/tests/jaeger/chunk/bug712265.js
+++ /dev/null
@@ -1,6 +0,0 @@
-// |jit-test| error: ReferenceError
-mjitChunkLimit(5);
-eval("\
-try { \
-  let (t1 = x) {}\
-}  finally {}");
diff --git a/js/src/jit/BaselineCompiler.cpp b/js/src/jit/BaselineCompiler.cpp
index 79420c41587..3237adb265c 100644
--- a/js/src/jit/BaselineCompiler.cpp
+++ b/js/src/jit/BaselineCompiler.cpp
@@ -155,7 +155,6 @@ BaselineCompiler::compile()
 
     for (size_t i = 0; i < pcMappingEntries_.length(); i++) {
         PCMappingEntry& entry = pcMappingEntries_[i];
-        entry.fixupNativeOffset(masm);
 
         if (entry.addIndexEntry) {
             PCMappingIndexEntry indexEntry;
@@ -190,16 +189,6 @@ BaselineCompiler::compile()
         return Method_Error;
     }
 
-    prologueOffset_.fixup(&masm);
-    epilogueOffset_.fixup(&masm);
-    profilerEnterFrameToggleOffset_.fixup(&masm);
-    profilerExitFrameToggleOffset_.fixup(&masm);
-#ifdef JS_TRACE_LOGGING
-    traceLoggerEnterToggleOffset_.fixup(&masm);
-    traceLoggerExitToggleOffset_.fixup(&masm);
-#endif
-    postDebugPrologueOffset_.fixup(&masm);
-
     // Note: There is an extra entry in the bytecode type map for the search hint, see below.
     size_t bytecodeTypeMapEntries = script->nTypeSets() + 1;
 
@@ -258,7 +247,6 @@ BaselineCompiler::compile()
     // Patch IC loads using IC entries.
     for (size_t i = 0; i < icLoadLabels_.length(); i++) {
         CodeOffsetLabel label = icLoadLabels_[i].label;
-        label.fixup(&masm);
         size_t icEntry = icLoadLabels_[i].icEntry;
         ICEntry* entryAddr = &(baselineScript->icEntry(icEntry));
         Assembler::PatchDataWithValueCheck(CodeLocationLabel(code, label),
diff --git a/js/src/jit/BaselineDebugModeOSR.cpp b/js/src/jit/BaselineDebugModeOSR.cpp
index 2884c81cd43..2610a8ddaaf 100644
--- a/js/src/jit/BaselineDebugModeOSR.cpp
+++ b/js/src/jit/BaselineDebugModeOSR.cpp
@@ -1168,7 +1168,6 @@ JitRuntime::generateBaselineDebugModeOSRHandler(JSContext* cx, uint32_t* noFrame
     if (!code)
         return nullptr;
 
-    noFrameRegPopOffset.fixup(&masm);
     *noFrameRegPopOffsetOut = noFrameRegPopOffset.offset();
 
 #ifdef JS_ION_PERF
diff --git a/js/src/jit/BaselineIC.cpp b/js/src/jit/BaselineIC.cpp
index 282c69e1a67..8e8c4080baf 100644
--- a/js/src/jit/BaselineIC.cpp
+++ b/js/src/jit/BaselineIC.cpp
@@ -6254,9 +6254,7 @@ ICGetProp_Fallback::Compiler::generateStubCode(MacroAssembler& masm)
 void
 ICGetProp_Fallback::Compiler::postGenerateStubCode(MacroAssembler& masm, Handle<JitCode*> code)
 {
-    CodeOffsetLabel offset(returnOffset_);
-    offset.fixup(&masm);
-    cx->compartment()->jitCompartment()->initBaselineGetPropReturnAddr(code->raw() + offset.offset());
+    cx->compartment()->jitCompartment()->initBaselineGetPropReturnAddr(code->raw() + returnOffset_);
 }
 
 bool
@@ -7753,9 +7751,7 @@ ICSetProp_Fallback::Compiler::generateStubCode(MacroAssembler& masm)
 void
 ICSetProp_Fallback::Compiler::postGenerateStubCode(MacroAssembler& masm, Handle<JitCode*> code)
 {
-    CodeOffsetLabel offset(returnOffset_);
-    offset.fixup(&masm);
-    cx->compartment()->jitCompartment()->initBaselineSetPropReturnAddr(code->raw() + offset.offset());
+    cx->compartment()->jitCompartment()->initBaselineSetPropReturnAddr(code->raw() + returnOffset_);
 }
 
 static void
@@ -9531,9 +9527,7 @@ ICCall_Fallback::Compiler::postGenerateStubCode(MacroAssembler& masm, Handle<Jit
     if (MOZ_UNLIKELY(isSpread_))
         return;
 
-    CodeOffsetLabel offset(returnOffset_);
-    offset.fixup(&masm);
-    cx->compartment()->jitCompartment()->initBaselineCallReturnAddr(code->raw() + offset.offset(),
+    cx->compartment()->jitCompartment()->initBaselineCallReturnAddr(code->raw() + returnOffset_,
                                                                     isConstructing_);
 }
 
diff --git a/js/src/jit/BaselineJIT.cpp b/js/src/jit/BaselineJIT.cpp
index 1bfc3cea20e..8ef1ebcff09 100644
--- a/js/src/jit/BaselineJIT.cpp
+++ b/js/src/jit/BaselineJIT.cpp
@@ -714,7 +714,6 @@ BaselineScript::copyICEntries(JSScript* script, const ICEntry* entries, MacroAss
     for (uint32_t i = 0; i < numICEntries(); i++) {
         ICEntry& realEntry = icEntry(i);
         realEntry = entries[i];
-        realEntry.fixupReturnOffset(masm);
 
         if (!realEntry.hasStub()) {
             // VM call without any stubs.
diff --git a/js/src/jit/CodeGenerator.cpp b/js/src/jit/CodeGenerator.cpp
index 8460932e3e0..aaa0aadcc91 100644
--- a/js/src/jit/CodeGenerator.cpp
+++ b/js/src/jit/CodeGenerator.cpp
@@ -8138,13 +8138,11 @@ CodeGenerator::link(JSContext* cx, CompilerConstraintList* constraints)
 
     {
         AutoWritableJitCode awjc(code);
-        invalidateEpilogueData_.fixup(&masm);
         Assembler::PatchDataWithValueCheck(CodeLocationLabel(code, invalidateEpilogueData_),
                                            ImmPtr(ionScript),
                                            ImmPtr((void*)-1));
 
         for (size_t i = 0; i < ionScriptLabels_.length(); i++) {
-            ionScriptLabels_[i].fixup(&masm);
             Assembler::PatchDataWithValueCheck(CodeLocationLabel(code, ionScriptLabels_[i]),
                                                ImmPtr(ionScript),
                                                ImmPtr((void*)-1));
@@ -8153,7 +8151,6 @@ CodeGenerator::link(JSContext* cx, CompilerConstraintList* constraints)
 #ifdef JS_TRACE_LOGGING
         TraceLoggerThread* logger = TraceLoggerForMainThread(cx->runtime());
         for (uint32_t i = 0; i < patchableTraceLoggers_.length(); i++) {
-            patchableTraceLoggers_[i].fixup(&masm);
             Assembler::PatchDataWithValueCheck(CodeLocationLabel(code, patchableTraceLoggers_[i]),
                                                ImmPtr(logger),
                                                ImmPtr(nullptr));
@@ -8165,7 +8162,6 @@ CodeGenerator::link(JSContext* cx, CompilerConstraintList* constraints)
             ionScript->setTraceLoggerEvent(event);
             uint32_t textId = event.payload()->textId();
             for (uint32_t i = 0; i < patchableTLScripts_.length(); i++) {
-                patchableTLScripts_[i].fixup(&masm);
                 Assembler::PatchDataWithValueCheck(CodeLocationLabel(code, patchableTLScripts_[i]),
                                                    ImmPtr((void*) uintptr_t(textId)),
                                                    ImmPtr((void*)0));
@@ -8175,11 +8171,9 @@ CodeGenerator::link(JSContext* cx, CompilerConstraintList* constraints)
         // Patch shared stub IC loads using IC entries
         for (size_t i = 0; i < sharedStubs_.length(); i++) {
             CodeOffsetLabel label = sharedStubs_[i].label;
-            label.fixup(&masm);
 
             IonICEntry& entry = ionScript->sharedStubList()[i];
             entry = sharedStubs_[i].entry;
-            entry.fixupReturnOffset(masm);
             Assembler::PatchDataWithValueCheck(CodeLocationLabel(code, label),
                                                ImmPtr(&entry),
                                                ImmPtr((void*)-1));
@@ -8203,8 +8197,7 @@ CodeGenerator::link(JSContext* cx, CompilerConstraintList* constraints)
     ionScript->setInvalidationEpilogueDataOffset(invalidateEpilogueData_.offset());
     ionScript->setOsrPc(gen->info().osrPc());
     ionScript->setOsrEntryOffset(getOsrEntryOffset());
-    ptrdiff_t real_invalidate = masm.actualOffset(invalidate_.offset());
-    ionScript->setInvalidationEpilogueOffset(real_invalidate);
+    ionScript->setInvalidationEpilogueOffset(invalidate_.offset());
 
     ionScript->setDeoptTable(deoptTable_);
 
diff --git a/js/src/jit/Ion.cpp b/js/src/jit/Ion.cpp
index 14f9151d40a..3f0b4fe2188 100644
--- a/js/src/jit/Ion.cpp
+++ b/js/src/jit/Ion.cpp
@@ -1116,14 +1116,10 @@ IonScript::copyPatchableBackedges(JSContext* cx, JitCode* code,
         PatchableBackedgeInfo& info = backedges[i];
         PatchableBackedge* patchableBackedge = &backedgeList()[i];
 
-        // Convert to actual offsets for the benefit of the ARM backend.
         info.backedge.fixup(&masm);
-        uint32_t loopHeaderOffset = masm.actualOffset(info.loopHeader->offset());
-        uint32_t interruptCheckOffset = masm.actualOffset(info.interruptCheck->offset());
-
         CodeLocationJump backedge(code, info.backedge);
-        CodeLocationLabel loopHeader(code, CodeOffsetLabel(loopHeaderOffset));
-        CodeLocationLabel interruptCheck(code, CodeOffsetLabel(interruptCheckOffset));
+        CodeLocationLabel loopHeader(code, CodeOffsetLabel(info.loopHeader->offset()));
+        CodeLocationLabel interruptCheck(code, CodeOffsetLabel(info.interruptCheck->offset()));
         new(patchableBackedge) PatchableBackedge(backedge, loopHeader, interruptCheck);
 
         // Point the backedge to either of its possible targets, according to
@@ -1147,16 +1143,12 @@ IonScript::copySafepointIndices(const SafepointIndex* si, MacroAssembler& masm)
     // final code address now.
     SafepointIndex* table = safepointIndices();
     memcpy(table, si, safepointIndexEntries_ * sizeof(SafepointIndex));
-    for (size_t i = 0; i < safepointIndexEntries_; i++)
-        table[i].adjustDisplacement(masm.actualOffset(table[i].displacement()));
 }
 
 void
 IonScript::copyOsiIndices(const OsiIndex* oi, MacroAssembler& masm)
 {
     memcpy(osiIndices(), oi, osiIndexEntries_ * sizeof(OsiIndex));
-    for (unsigned i = 0; i < osiIndexEntries_; i++)
-        osiIndices()[i].fixUpOffset(masm);
 }
 
 void
diff --git a/js/src/jit/IonCaches.cpp b/js/src/jit/IonCaches.cpp
index 584a2982a4b..122d1a46ace 100644
--- a/js/src/jit/IonCaches.cpp
+++ b/js/src/jit/IonCaches.cpp
@@ -51,7 +51,7 @@ CodeLocationJump::repoint(JitCode* code, MacroAssembler* masm)
 #ifdef JS_CODEGEN_X64
         MOZ_ASSERT((uint64_t)raw_ <= UINT32_MAX);
 #endif
-        new_off = masm->actualOffset((uintptr_t)raw_);
+        new_off = (uintptr_t)raw_;
 #ifdef JS_SMALL_BRANCH
         jumpTableEntryOffset = masm->actualIndex(jumpTableEntryOffset);
 #endif
@@ -72,7 +72,7 @@ CodeLocationLabel::repoint(JitCode* code, MacroAssembler* masm)
 #ifdef JS_CODEGEN_X64
         MOZ_ASSERT((uint64_t)raw_ <= UINT32_MAX);
 #endif
-        new_off = masm->actualOffset((uintptr_t)raw_);
+        new_off = (uintptr_t)raw_;
      }
      MOZ_ASSERT(new_off < code->instructionsSize());
 
@@ -80,16 +80,9 @@ CodeLocationLabel::repoint(JitCode* code, MacroAssembler* masm)
      setAbsolute();
 }
 
-void
-CodeOffsetLabel::fixup(MacroAssembler* masm)
-{
-     offset_ = masm->actualOffset(offset_);
-}
-
 void
 CodeOffsetJump::fixup(MacroAssembler* masm)
 {
-     offset_ = masm->actualOffset(offset_);
 #ifdef JS_SMALL_BRANCH
      jumpTableIndex_ = masm->actualIndex(jumpTableIndex_);
 #endif
@@ -251,10 +244,9 @@ class IonCache::StubAttacher
         PatchJump(rejoinJump, rejoinLabel_);
     }
 
-    void patchStubCodePointer(MacroAssembler& masm, JitCode* code) {
+    void patchStubCodePointer(JitCode* code) {
         if (hasStubCodePatchOffset_) {
             AutoWritableJitCode awjc(code);
-            stubCodePatchOffset_.fixup(&masm);
             Assembler::PatchDataWithValueCheck(CodeLocationLabel(code, stubCodePatchOffset_),
                                                ImmPtr(code), STUB_ADDR);
         }
@@ -305,7 +297,7 @@ IonCache::attachStub(MacroAssembler& masm, StubAttacher& attacher, Handle<JitCod
     // Replace the STUB_ADDR constant by the address of the generated stub, such
     // as it can be kept alive even if the cache is flushed (see
     // MarkJitExitFrame).
-    attacher.patchStubCodePointer(masm, code);
+    attacher.patchStubCodePointer(code);
 
     // Update the failure path.
     attacher.patchNextStubJump(masm, code);
@@ -350,6 +342,7 @@ IonCache::linkAndAttachStub(JSContext* cx, MacroAssembler& masm, StubAttacher& a
         JitcodeGlobalTable* globalTable = cx->runtime()->jitRuntime()->getJitcodeGlobalTable();
         if (!globalTable->addEntry(entry, cx->runtime())) {
             entry.destroy();
+            ReportOutOfMemory(cx);
             return false;
         }
 
@@ -363,6 +356,7 @@ IonCache::linkAndAttachStub(JSContext* cx, MacroAssembler& masm, StubAttacher& a
         JitcodeGlobalTable* globalTable = cx->runtime()->jitRuntime()->getJitcodeGlobalTable();
         if (!globalTable->addEntry(entry, cx->runtime())) {
             entry.destroy();
+            ReportOutOfMemory(cx);
             return false;
         }
 
@@ -370,6 +364,13 @@ IonCache::linkAndAttachStub(JSContext* cx, MacroAssembler& masm, StubAttacher& a
         code->setHasBytecodeMap();
     }
 
+    // Report masm OOM errors here, so all our callers can:
+    // return linkAndAttachStub(...);
+    if (masm.oom()) {
+        ReportOutOfMemory(cx);
+        return false;
+    }
+
     return true;
 }
 
diff --git a/js/src/jit/JitFrames.cpp b/js/src/jit/JitFrames.cpp
index e71531c4ff4..a33c980bdf6 100644
--- a/js/src/jit/JitFrames.cpp
+++ b/js/src/jit/JitFrames.cpp
@@ -1683,12 +1683,6 @@ GetPcScript(JSContext* cx, JSScript** scriptRes, jsbytecode** pcRes)
         rt->ionPcScriptCache->add(hash, retAddr, pc, *scriptRes);
 }
 
-void
-OsiIndex::fixUpOffset(MacroAssembler& masm)
-{
-    callPointDisplacement_ = masm.actualOffset(callPointDisplacement_);
-}
-
 uint32_t
 OsiIndex::returnPointDisplacement() const
 {
diff --git a/js/src/jit/JitFrames.h b/js/src/jit/JitFrames.h
index 69e549e97d2..41698a99934 100644
--- a/js/src/jit/JitFrames.h
+++ b/js/src/jit/JitFrames.h
@@ -173,7 +173,6 @@ class OsiIndex
     uint32_t snapshotOffset() const {
         return snapshotOffset_;
     }
-    void fixUpOffset(MacroAssembler& masm);
 };
 
 // The layout of an Ion frame on the C stack is roughly:
diff --git a/js/src/jit/LIR.h b/js/src/jit/LIR.h
index 1a68d692127..e88accdbd59 100644
--- a/js/src/jit/LIR.h
+++ b/js/src/jit/LIR.h
@@ -1595,9 +1595,6 @@ class LSafepoint : public TempObject
         MOZ_ASSERT(!osiCallPointOffset_);
         osiCallPointOffset_ = osiCallPointOffset;
     }
-    void fixupOffset(MacroAssembler* masm) {
-        osiCallPointOffset_ = masm->actualOffset(osiCallPointOffset_);
-    }
 };
 
 class LInstruction::InputIterator
diff --git a/js/src/jit/MacroAssembler.cpp b/js/src/jit/MacroAssembler.cpp
index 7d0c9575049..29541853c1e 100644
--- a/js/src/jit/MacroAssembler.cpp
+++ b/js/src/jit/MacroAssembler.cpp
@@ -2192,7 +2192,6 @@ MacroAssembler::linkProfilerCallSites(JitCode* code)
 {
     for (size_t i = 0; i < profilerCallSites_.length(); i++) {
         CodeOffsetLabel offset = profilerCallSites_[i];
-        offset.fixup(this);
         CodeLocationLabel location(code, offset);
         PatchDataWithValueCheck(location, ImmPtr(location.raw()), ImmPtr((void*)-1));
     }
@@ -2628,7 +2627,6 @@ MacroAssembler::linkSelfReference(JitCode* code)
     // the JitCode onto the stack in order to GC it correctly.  exitCodePatch should
     // be unset if the code never needed to push its JitCode*.
     if (hasSelfReference()) {
-        selfReferencePatch_.fixup(this);
         PatchDataWithValueCheck(CodeLocationLabel(code, selfReferencePatch_),
                                 ImmPtr(code),
                                 ImmPtr((void*)-1));
diff --git a/js/src/jit/PerfSpewer.cpp b/js/src/jit/PerfSpewer.cpp
index 64d538d6189..36b0da332a4 100644
--- a/js/src/jit/PerfSpewer.cpp
+++ b/js/src/jit/PerfSpewer.cpp
@@ -223,11 +223,11 @@ PerfSpewer::writeProfile(JSScript* script,
 
         uint32_t thisFunctionIndex = nextFunctionIndex++;
         uintptr_t funcStart = uintptr_t(code->raw());
-        uintptr_t funcEndInlineCode = funcStart + masm.actualOffset(endInlineCode.offset());
+        uintptr_t funcEndInlineCode = funcStart + endInlineCode.offset();
         uintptr_t funcEnd = funcStart + code->instructionsSize();
 
         // function begins with the prologue, which is located before the first basic block
-        size_t prologueSize = masm.actualOffset(basicBlocks_[0].start.offset());
+        size_t prologueSize = basicBlocks_[0].start.offset();
 
         if (prologueSize > 0) {
             fprintf(PerfFilePtr, "%" PRIxSIZE " %" PRIxSIZE " %s:%" PRIuSIZE ": Func%02d-Prologue\n",
@@ -238,8 +238,8 @@ PerfSpewer::writeProfile(JSScript* script,
         for (uint32_t i = 0; i < basicBlocks_.length(); i++) {
             Record& r = basicBlocks_[i];
 
-            uintptr_t blockStart = funcStart + masm.actualOffset(r.start.offset());
-            uintptr_t blockEnd = funcStart + masm.actualOffset(r.end.offset());
+            uintptr_t blockStart = funcStart + r.start.offset();
+            uintptr_t blockEnd = funcStart + r.end.offset();
 
             MOZ_ASSERT(cur <= blockStart);
             if (cur < blockStart) {
diff --git a/js/src/jit/SharedIC.h b/js/src/jit/SharedIC.h
index 447419514c2..84d97414064 100644
--- a/js/src/jit/SharedIC.h
+++ b/js/src/jit/SharedIC.h
@@ -286,13 +286,6 @@ class ICEntry
         returnOffset_ = (uint32_t) offset.offset();
     }
 
-    void fixupReturnOffset(MacroAssembler& masm) {
-        CodeOffsetLabel offset = returnOffset();
-        offset.fixup(&masm);
-        MOZ_ASSERT(offset.offset() <= UINT32_MAX);
-        returnOffset_ = (uint32_t) offset.offset();
-    }
-
     uint32_t pcOffset() const {
         return pcOffset_;
     }
diff --git a/js/src/jit/arm/Assembler-arm.cpp b/js/src/jit/arm/Assembler-arm.cpp
index f9d22edeac2..26d7b00d5a2 100644
--- a/js/src/jit/arm/Assembler-arm.cpp
+++ b/js/src/jit/arm/Assembler-arm.cpp
@@ -631,24 +631,6 @@ Assembler::finish()
     flush();
     MOZ_ASSERT(!isFinished);
     isFinished = true;
-
-    for (unsigned int i = 0; i < tmpDataRelocations_.length(); i++) {
-        size_t offset = tmpDataRelocations_[i].getOffset();
-        size_t real_offset = offset + m_buffer.poolSizeBefore(offset);
-        dataRelocations_.writeUnsigned(real_offset);
-    }
-
-    for (unsigned int i = 0; i < tmpJumpRelocations_.length(); i++) {
-        size_t offset = tmpJumpRelocations_[i].getOffset();
-        size_t real_offset = offset + m_buffer.poolSizeBefore(offset);
-        jumpRelocations_.writeUnsigned(real_offset);
-    }
-
-    for (unsigned int i = 0; i < tmpPreBarriers_.length(); i++) {
-        size_t offset = tmpPreBarriers_[i].getOffset();
-        size_t real_offset = offset + m_buffer.poolSizeBefore(offset);
-        preBarriers_.writeUnsigned(real_offset);
-    }
 }
 
 void
@@ -659,12 +641,6 @@ Assembler::executableCopy(uint8_t* buffer)
     AutoFlushICache::setRange(uintptr_t(buffer), m_buffer.size());
 }
 
-uint32_t
-Assembler::actualOffset(uint32_t off_) const
-{
-    return off_ + m_buffer.poolSizeBefore(off_);
-}
-
 uint32_t
 Assembler::actualIndex(uint32_t idx_) const
 {
@@ -678,12 +654,6 @@ Assembler::PatchableJumpAddress(JitCode* code, uint32_t pe_)
     return code->raw() + pe_;
 }
 
-BufferOffset
-Assembler::actualOffset(BufferOffset off_) const
-{
-    return BufferOffset(off_.getOffset() + m_buffer.poolSizeBefore(off_.getOffset()));
-}
-
 class RelocationIterator
 {
     CompactBufferReader reader_;
@@ -908,12 +878,11 @@ TraceDataRelocations(JSTracer* trc, uint8_t* buffer, CompactBufferReader& reader
 }
 
 static void
-TraceDataRelocations(JSTracer* trc, ARMBuffer* buffer,
-                     Vector<BufferOffset, 0, SystemAllocPolicy>* locs)
+TraceDataRelocations(JSTracer* trc, ARMBuffer* buffer, CompactBufferReader& reader)
 {
-    for (unsigned int idx = 0; idx < locs->length(); idx++) {
-        BufferOffset bo = (*locs)[idx];
-        ARMBuffer::AssemblerBufferInstIterator iter(bo, buffer);
+    while (reader.more()) {
+        BufferOffset offset(reader.readUnsigned());
+        ARMBuffer::AssemblerBufferInstIterator iter(offset, buffer);
         TraceOneDataRelocation(trc, &iter);
     }
 }
@@ -957,8 +926,10 @@ Assembler::trace(JSTracer* trc)
         }
     }
 
-    if (tmpDataRelocations_.length())
-        ::TraceDataRelocations(trc, &m_buffer, &tmpDataRelocations_);
+    if (dataRelocations_.length()) {
+        CompactBufferReader reader(dataRelocations_);
+        ::TraceDataRelocations(trc, &m_buffer, reader);
+    }
 }
 
 void
@@ -966,7 +937,7 @@ Assembler::processCodeLabels(uint8_t* rawCode)
 {
     for (size_t i = 0; i < codeLabels_.length(); i++) {
         CodeLabel label = codeLabels_[i];
-        Bind(rawCode, label.dest(), rawCode + actualOffset(label.src()->offset()));
+        Bind(rawCode, label.dest(), rawCode + label.src()->offset());
     }
 }
 
@@ -988,8 +959,7 @@ void
 Assembler::Bind(uint8_t* rawCode, AbsoluteLabel* label, const void* address)
 {
     // See writeCodePointer comment.
-    uint32_t off = actualOffset(label->offset());
-    *reinterpret_cast<const void**>(rawCode + off) = address;
+    *reinterpret_cast<const void**>(rawCode + label->offset()) = address;
 }
 
 Assembler::Condition
diff --git a/js/src/jit/arm/Assembler-arm.h b/js/src/jit/arm/Assembler-arm.h
index ce8a2da46f7..6b5137090c5 100644
--- a/js/src/jit/arm/Assembler-arm.h
+++ b/js/src/jit/arm/Assembler-arm.h
@@ -1251,10 +1251,8 @@ class Assembler : public AssemblerShared
 
   public:
     void resetCounter();
-    uint32_t actualOffset(uint32_t) const;
     uint32_t actualIndex(uint32_t) const;
     static uint8_t* PatchableJumpAddress(JitCode* code, uint32_t index);
-    BufferOffset actualOffset(BufferOffset) const;
     static uint32_t NopFill;
     static uint32_t GetNopFill();
     static uint32_t AsmPoolMaxOffset;
@@ -1275,9 +1273,6 @@ class Assembler : public AssemblerShared
     // TODO: this should actually be a pool-like object. It is currently a big
     // hack, and probably shouldn't exist.
     js::Vector<RelativePatch, 8, SystemAllocPolicy> jumps_;
-    js::Vector<BufferOffset, 0, SystemAllocPolicy> tmpJumpRelocations_;
-    js::Vector<BufferOffset, 0, SystemAllocPolicy> tmpDataRelocations_;
-    js::Vector<BufferOffset, 0, SystemAllocPolicy> tmpPreBarriers_;
 
     CompactBufferWriter jumpRelocations_;
     CompactBufferWriter dataRelocations_;
@@ -1342,7 +1337,7 @@ class Assembler : public AssemblerShared
     // MacroAssemblers hold onto gcthings, so they are traced by the GC.
     void trace(JSTracer* trc);
     void writeRelocation(BufferOffset src) {
-        tmpJumpRelocations_.append(src);
+        jumpRelocations_.writeUnsigned(src.getOffset());
     }
 
     // As opposed to x86/x64 version, the data relocation has to be executed
@@ -1352,11 +1347,11 @@ class Assembler : public AssemblerShared
             if (gc::IsInsideNursery(ptr.value))
                 embedsNurseryPointers_ = true;
             if (ptr.value)
-                tmpDataRelocations_.append(nextOffset());
+                dataRelocations_.writeUnsigned(nextOffset().getOffset());
         }
     }
     void writePrebarrierOffset(CodeOffsetLabel label) {
-        tmpPreBarriers_.append(BufferOffset(label.offset()));
+        preBarriers_.writeUnsigned(label.offset());
     }
 
     enum RelocBranchStyle {
@@ -1699,7 +1694,7 @@ class Assembler : public AssemblerShared
 
     // See Bind
     size_t labelOffsetToPatchOffset(size_t offset) {
-        return actualOffset(offset);
+        return offset;
     }
 
     void as_bkpt();
diff --git a/js/src/jit/arm/Trampoline-arm.cpp b/js/src/jit/arm/Trampoline-arm.cpp
index 6faa21777b9..5e24fbfbff2 100644
--- a/js/src/jit/arm/Trampoline-arm.cpp
+++ b/js/src/jit/arm/Trampoline-arm.cpp
@@ -569,10 +569,8 @@ JitRuntime::generateArgumentsRectifier(JSContext* cx, void** returnAddrOut)
     AutoFlushICache afc("ArgumentsRectifier");
     JitCode* code = linker.newCode<NoGC>(cx, OTHER_CODE);
 
-    CodeOffsetLabel returnLabel(returnOffset);
-    returnLabel.fixup(&masm);
     if (returnAddrOut)
-        *returnAddrOut = (void*) (code->raw() + returnLabel.offset());
+        *returnAddrOut = (void*) (code->raw() + returnOffset);
 
 #ifdef JS_ION_PERF
     writePerfSpewerJitCodeProfile(code, "ArgumentsRectifier");
diff --git a/js/src/jit/arm64/Assembler-arm64.cpp b/js/src/jit/arm64/Assembler-arm64.cpp
index 27b81d836bc..b8e3a4b1482 100644
--- a/js/src/jit/arm64/Assembler-arm64.cpp
+++ b/js/src/jit/arm64/Assembler-arm64.cpp
@@ -83,22 +83,13 @@ Assembler::finish()
 
     // The jump relocation table starts with a fixed-width integer pointing
     // to the start of the extended jump table.
-    if (tmpJumpRelocations_.length())
-        jumpRelocations_.writeFixedUint32_t(toFinalOffset(ExtendedJumpTable_));
-
-    for (unsigned int i = 0; i < tmpJumpRelocations_.length(); i++) {
-        JumpRelocation& reloc = tmpJumpRelocations_[i];
-
-        // Each entry in the relocations table is an (offset, extendedTableIndex) pair.
-        jumpRelocations_.writeUnsigned(toFinalOffset(reloc.jump));
-        jumpRelocations_.writeUnsigned(reloc.extendedTableIndex);
+    // Space for this integer is allocated by Assembler::addJumpRelocation()
+    // before writing the first entry.
+    // Don't touch memory if we saw an OOM error.
+    if (jumpRelocations_.length() && !oom()) {
+        MOZ_ASSERT(jumpRelocations_.length() >= sizeof(uint32_t));
+        *(uint32_t*)jumpRelocations_.buffer() = ExtendedJumpTable_.getOffset();
     }
-
-    for (unsigned int i = 0; i < tmpDataRelocations_.length(); i++)
-        dataRelocations_.writeUnsigned(toFinalOffset(tmpDataRelocations_[i]));
-
-    for (unsigned int i = 0; i < tmpPreBarriers_.length(); i++)
-        preBarriers_.writeUnsigned(toFinalOffset(tmpPreBarriers_[i]));
 }
 
 BufferOffset
@@ -159,9 +150,9 @@ Assembler::executableCopy(uint8_t* buffer)
         }
 
         Instruction* target = (Instruction*)rp.target;
-        Instruction* branch = (Instruction*)(buffer + toFinalOffset(rp.offset));
+        Instruction* branch = (Instruction*)(buffer + rp.offset.getOffset());
         JumpTableEntry* extendedJumpTable =
-            reinterpret_cast<JumpTableEntry*>(buffer + toFinalOffset(ExtendedJumpTable_));
+            reinterpret_cast<JumpTableEntry*>(buffer + ExtendedJumpTable_.getOffset());
         if (branch->BranchType() != vixl::UnknownBranchType) {
             if (branch->IsTargetReachable(target)) {
                 branch->SetImmPCOffsetTarget(target);
@@ -301,8 +292,16 @@ Assembler::addJumpRelocation(BufferOffset src, Relocation::Kind reloc)
     // Only JITCODE relocations are patchable at runtime.
     MOZ_ASSERT(reloc == Relocation::JITCODE);
 
-    // Each relocation requires an entry in the extended jump table.
-    tmpJumpRelocations_.append(JumpRelocation(src, pendingJumps_.length()));
+    // The jump relocation table starts with a fixed-width integer pointing
+    // to the start of the extended jump table. But, we don't know the
+    // actual extended jump table offset yet, so write a 0 which we'll
+    // patch later in Assembler::finish().
+    if (!jumpRelocations_.length())
+        jumpRelocations_.writeFixedUint32_t(0);
+
+    // Each entry in the table is an (offset, extendedTableIndex) pair.
+    jumpRelocations_.writeUnsigned(src.getOffset());
+    jumpRelocations_.writeUnsigned(pendingJumps_.length());
 }
 
 void
diff --git a/js/src/jit/arm64/Assembler-arm64.h b/js/src/jit/arm64/Assembler-arm64.h
index 58f573ff5ed..ca2e0802663 100644
--- a/js/src/jit/arm64/Assembler-arm64.h
+++ b/js/src/jit/arm64/Assembler-arm64.h
@@ -236,13 +236,12 @@ class Assembler : public vixl::Assembler
     void processCodeLabels(uint8_t* rawCode) {
         for (size_t i = 0; i < codeLabels_.length(); i++) {
             CodeLabel label = codeLabels_[i];
-            Bind(rawCode, label.dest(), rawCode + actualOffset(label.src()->offset()));
+            Bind(rawCode, label.dest(), rawCode + label.src()->offset());
         }
     }
 
     void Bind(uint8_t* rawCode, AbsoluteLabel* label, const void* address) {
-        uint32_t off = actualOffset(label->offset());
-        *reinterpret_cast<const void**>(rawCode + off) = address;
+        *reinterpret_cast<const void**>(rawCode + label->offset()) = address;
     }
     bool nextLink(BufferOffset cur, BufferOffset* next) {
         Instruction* link = getInstructionAt(cur);
@@ -260,16 +259,11 @@ class Assembler : public vixl::Assembler
         armbuffer_.flushPool();
     }
 
-    int actualOffset(int curOffset) {
-        return curOffset + armbuffer_.poolSizeBefore(curOffset);
-    }
     int actualIndex(int curOffset) {
         ARMBuffer::PoolEntry pe(curOffset);
         return armbuffer_.poolEntryOffset(pe);
     }
-    int labelOffsetToPatchOffset(int labelOff) {
-        return actualOffset(labelOff);
-    }
+    size_t labelOffsetToPatchOffset(size_t labelOff) { return labelOff; }
     static uint8_t* PatchableJumpAddress(JitCode* code, uint32_t index) {
         return code->raw() + index;
     }
@@ -344,11 +338,6 @@ class Assembler : public vixl::Assembler
     static void FixupNurseryObjects(JSContext* cx, JitCode* code, CompactBufferReader& reader,
                                     const ObjectVector& nurseryObjects);
 
-    // Convert a BufferOffset to a final byte offset from the start of the code buffer.
-    size_t toFinalOffset(BufferOffset offset) {
-        return size_t(offset.getOffset() + armbuffer_.poolSizeBefore(offset.getOffset()));
-    }
-
   public:
     // A Jump table entry is 2 instructions, with 8 bytes of raw data
     static const size_t SizeOfJumpTableEntry = 16;
@@ -404,13 +393,6 @@ class Assembler : public vixl::Assembler
         { }
     };
 
-    // Because ARM and A64 use a code buffer that allows for constant pool insertion,
-    // the actual offset of each jump cannot be known until finalization.
-    // These vectors store the WIP offsets.
-    js::Vector<BufferOffset, 0, SystemAllocPolicy> tmpDataRelocations_;
-    js::Vector<BufferOffset, 0, SystemAllocPolicy> tmpPreBarriers_;
-    js::Vector<JumpRelocation, 0, SystemAllocPolicy> tmpJumpRelocations_;
-
     // Structure for fixing up pc-relative loads/jumps when the machine
     // code gets moved (executable copy, gc, etc.).
     struct RelativePatch
diff --git a/js/src/jit/arm64/MacroAssembler-arm64.h b/js/src/jit/arm64/MacroAssembler-arm64.h
index 7edabb49189..6434cbc079f 100644
--- a/js/src/jit/arm64/MacroAssembler-arm64.h
+++ b/js/src/jit/arm64/MacroAssembler-arm64.h
@@ -2532,19 +2532,19 @@ class MacroAssemblerCompat : public vixl::MacroAssembler
     // load: offset to the load instruction obtained by movePatchablePtr().
     void writeDataRelocation(ImmGCPtr ptr, BufferOffset load) {
         if (ptr.value)
-            tmpDataRelocations_.append(load);
+            dataRelocations_.writeUnsigned(load.getOffset());
     }
     void writeDataRelocation(const Value& val, BufferOffset load) {
         if (val.isMarkable()) {
             gc::Cell* cell = reinterpret_cast<gc::Cell*>(val.toGCThing());
             if (cell && gc::IsInsideNursery(cell))
                 embedsNurseryPointers_ = true;
-            tmpDataRelocations_.append(load);
+            dataRelocations_.writeUnsigned(load.getOffset());
         }
     }
 
     void writePrebarrierOffset(CodeOffsetLabel label) {
-        tmpPreBarriers_.append(BufferOffset(label.offset()));
+        preBarriers_.writeUnsigned(label.offset());
     }
 
     void computeEffectiveAddress(const Address& address, Register dest) {
diff --git a/js/src/jit/arm64/Trampoline-arm64.cpp b/js/src/jit/arm64/Trampoline-arm64.cpp
index d4aa1691881..7b18be7b807 100644
--- a/js/src/jit/arm64/Trampoline-arm64.cpp
+++ b/js/src/jit/arm64/Trampoline-arm64.cpp
@@ -422,11 +422,8 @@ JitRuntime::generateArgumentsRectifier(JSContext* cx, void** returnAddrOut)
     Linker linker(masm);
     JitCode* code = linker.newCode<NoGC>(cx, OTHER_CODE);
 
-    if (returnAddrOut) {
-        CodeOffsetLabel returnLabel(returnOffset);
-        returnLabel.fixup(&masm);
-        *returnAddrOut = (void*) (code->raw() + returnLabel.offset());
-    }
+    if (returnAddrOut)
+        *returnAddrOut = (void*) (code->raw() + returnOffset);
 
     return code;
 }
diff --git a/js/src/jit/arm64/vixl/MozBaseAssembler-vixl.h b/js/src/jit/arm64/vixl/MozBaseAssembler-vixl.h
index 5ee22ee01c5..6c24d979944 100644
--- a/js/src/jit/arm64/vixl/MozBaseAssembler-vixl.h
+++ b/js/src/jit/arm64/vixl/MozBaseAssembler-vixl.h
@@ -188,9 +188,6 @@ class MozBaseAssembler : public js::jit::AssemblerShared {
   js::jit::CompactBufferWriter dataRelocations_;
   js::jit::CompactBufferWriter relocations_;
   js::jit::CompactBufferWriter preBarriers_;
-
-  // Literal pools.
-  mozilla::Array<js::jit::Pool, 4> pools_;
 };
 
 
diff --git a/js/src/jit/mips-shared/Assembler-mips-shared.cpp b/js/src/jit/mips-shared/Assembler-mips-shared.cpp
index a1aebb6175d..a342cb6bc56 100644
--- a/js/src/jit/mips-shared/Assembler-mips-shared.cpp
+++ b/js/src/jit/mips-shared/Assembler-mips-shared.cpp
@@ -88,12 +88,6 @@ AssemblerMIPSShared::finish()
     isFinished = true;
 }
 
-uint32_t
-AssemblerMIPSShared::actualOffset(uint32_t off_) const
-{
-    return off_;
-}
-
 uint32_t
 AssemblerMIPSShared::actualIndex(uint32_t idx_) const
 {
@@ -138,7 +132,7 @@ AssemblerMIPSShared::processCodeLabels(uint8_t* rawCode)
 {
     for (size_t i = 0; i < codeLabels_.length(); i++) {
         CodeLabel label = codeLabels_[i];
-        asAsm().Bind(rawCode, label.dest(), rawCode + actualOffset(label.src()->offset()));
+        asAsm().Bind(rawCode, label.dest(), rawCode + label.src()->offset());
     }
 }
 
diff --git a/js/src/jit/mips-shared/Assembler-mips-shared.h b/js/src/jit/mips-shared/Assembler-mips-shared.h
index 4a9d0bb062c..a390ef4504b 100644
--- a/js/src/jit/mips-shared/Assembler-mips-shared.h
+++ b/js/src/jit/mips-shared/Assembler-mips-shared.h
@@ -732,7 +732,6 @@ class AssemblerMIPSShared : public AssemblerShared
         return m_buffer.getInst(bo);
     }
   public:
-    uint32_t actualOffset(uint32_t) const;
     uint32_t actualIndex(uint32_t) const;
     static uint8_t* PatchableJumpAddress(JitCode* code, uint32_t index);
   protected:
@@ -1043,9 +1042,7 @@ class AssemblerMIPSShared : public AssemblerShared
     void retarget(Label* label, Label* target);
 
     // See Bind
-    size_t labelOffsetToPatchOffset(size_t offset) {
-        return actualOffset(offset);
-    }
+    size_t labelOffsetToPatchOffset(size_t offset) { return offset; }
 
     void call(Label* label);
     void call(void* target);
diff --git a/js/src/jit/mips-shared/Bailouts-mips-shared.cpp b/js/src/jit/mips-shared/Bailouts-mips-shared.cpp
index 16042181b29..7d8c2a76daa 100644
--- a/js/src/jit/mips-shared/Bailouts-mips-shared.cpp
+++ b/js/src/jit/mips-shared/Bailouts-mips-shared.cpp
@@ -4,10 +4,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#include "jit/mips-shared/Bailouts-mips-shared.h"
-
-#include "jscntxt.h"
-#include "jscompartment.h"
+#include "jit/Bailouts.h"
 
 using namespace js;
 using namespace js::jit;
diff --git a/js/src/jit/mips-shared/MacroAssembler-mips-shared.cpp b/js/src/jit/mips-shared/MacroAssembler-mips-shared.cpp
new file mode 100644
index 00000000000..c1ebee2b9f5
--- /dev/null
+++ b/js/src/jit/mips-shared/MacroAssembler-mips-shared.cpp
@@ -0,0 +1,790 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "jit/mips-shared/MacroAssembler-mips-shared.h"
+
+using namespace js;
+using namespace jit;
+
+void
+MacroAssemblerMIPSShared::ma_move(Register rd, Register rs)
+{
+    as_or(rd, rs, zero);
+}
+
+void
+MacroAssemblerMIPSShared::ma_li(Register dest, ImmGCPtr ptr)
+{
+    writeDataRelocation(ptr);
+    asMasm().ma_liPatchable(dest, ImmPtr(ptr.value));
+}
+
+void
+MacroAssemblerMIPSShared::ma_li(Register dest, Imm32 imm)
+{
+    if (Imm16::IsInSignedRange(imm.value)) {
+        as_addiu(dest, zero, imm.value);
+    } else if (Imm16::IsInUnsignedRange(imm.value)) {
+        as_ori(dest, zero, Imm16::Lower(imm).encode());
+    } else if (Imm16::Lower(imm).encode() == 0) {
+        as_lui(dest, Imm16::Upper(imm).encode());
+    } else {
+        as_lui(dest, Imm16::Upper(imm).encode());
+        as_ori(dest, dest, Imm16::Lower(imm).encode());
+    }
+}
+
+// Shifts
+void
+MacroAssemblerMIPSShared::ma_sll(Register rd, Register rt, Imm32 shift)
+{
+    as_sll(rd, rt, shift.value % 32);
+}
+void
+MacroAssemblerMIPSShared::ma_srl(Register rd, Register rt, Imm32 shift)
+{
+    as_srl(rd, rt, shift.value % 32);
+}
+
+void
+MacroAssemblerMIPSShared::ma_sra(Register rd, Register rt, Imm32 shift)
+{
+    as_sra(rd, rt, shift.value % 32);
+}
+
+void
+MacroAssemblerMIPSShared::ma_ror(Register rd, Register rt, Imm32 shift)
+{
+    as_rotr(rd, rt, shift.value % 32);
+}
+
+void
+MacroAssemblerMIPSShared::ma_rol(Register rd, Register rt, Imm32 shift)
+{
+    as_rotr(rd, rt, 32 - (shift.value % 32));
+}
+
+void
+MacroAssemblerMIPSShared::ma_sll(Register rd, Register rt, Register shift)
+{
+    as_sllv(rd, rt, shift);
+}
+
+void
+MacroAssemblerMIPSShared::ma_srl(Register rd, Register rt, Register shift)
+{
+    as_srlv(rd, rt, shift);
+}
+
+void
+MacroAssemblerMIPSShared::ma_sra(Register rd, Register rt, Register shift)
+{
+    as_srav(rd, rt, shift);
+}
+
+void
+MacroAssemblerMIPSShared::ma_ror(Register rd, Register rt, Register shift)
+{
+    as_rotrv(rd, rt, shift);
+}
+
+void
+MacroAssemblerMIPSShared::ma_rol(Register rd, Register rt, Register shift)
+{
+    ma_negu(ScratchRegister, shift);
+    as_rotrv(rd, rt, ScratchRegister);
+}
+
+void
+MacroAssemblerMIPSShared::ma_negu(Register rd, Register rs)
+{
+    as_subu(rd, zero, rs);
+}
+
+void
+MacroAssemblerMIPSShared::ma_not(Register rd, Register rs)
+{
+    as_nor(rd, rs, zero);
+}
+
+// And.
+void
+MacroAssemblerMIPSShared::ma_and(Register rd, Register rs)
+{
+    as_and(rd, rd, rs);
+}
+
+void
+MacroAssemblerMIPSShared::ma_and(Register rd, Imm32 imm)
+{
+    ma_and(rd, rd, imm);
+}
+
+void
+MacroAssemblerMIPSShared::ma_and(Register rd, Register rs, Imm32 imm)
+{
+    if (Imm16::IsInUnsignedRange(imm.value)) {
+        as_andi(rd, rs, imm.value);
+    } else {
+        ma_li(ScratchRegister, imm);
+        as_and(rd, rs, ScratchRegister);
+    }
+}
+
+// Or.
+void
+MacroAssemblerMIPSShared::ma_or(Register rd, Register rs)
+{
+    as_or(rd, rd, rs);
+}
+
+void
+MacroAssemblerMIPSShared::ma_or(Register rd, Imm32 imm)
+{
+    ma_or(rd, rd, imm);
+}
+
+void
+MacroAssemblerMIPSShared::ma_or(Register rd, Register rs, Imm32 imm)
+{
+    if (Imm16::IsInUnsignedRange(imm.value)) {
+        as_ori(rd, rs, imm.value);
+    } else {
+        ma_li(ScratchRegister, imm);
+        as_or(rd, rs, ScratchRegister);
+    }
+}
+
+// xor
+void
+MacroAssemblerMIPSShared::ma_xor(Register rd, Register rs)
+{
+    as_xor(rd, rd, rs);
+}
+
+void
+MacroAssemblerMIPSShared::ma_xor(Register rd, Imm32 imm)
+{
+    ma_xor(rd, rd, imm);
+}
+
+void
+MacroAssemblerMIPSShared::ma_xor(Register rd, Register rs, Imm32 imm)
+{
+    if (Imm16::IsInUnsignedRange(imm.value)) {
+        as_xori(rd, rs, imm.value);
+    } else {
+        ma_li(ScratchRegister, imm);
+        as_xor(rd, rs, ScratchRegister);
+    }
+}
+
+// Arithmetic-based ops.
+
+// Add.
+void
+MacroAssemblerMIPSShared::ma_addu(Register rd, Register rs, Imm32 imm)
+{
+    if (Imm16::IsInSignedRange(imm.value)) {
+        as_addiu(rd, rs, imm.value);
+    } else {
+        ma_li(ScratchRegister, imm);
+        as_addu(rd, rs, ScratchRegister);
+    }
+}
+
+void
+MacroAssemblerMIPSShared::ma_addu(Register rd, Register rs)
+{
+    as_addu(rd, rd, rs);
+}
+
+void
+MacroAssemblerMIPSShared::ma_addu(Register rd, Imm32 imm)
+{
+    ma_addu(rd, rd, imm);
+}
+
+// Subtract.
+void
+MacroAssemblerMIPSShared::ma_subu(Register rd, Register rs, Imm32 imm)
+{
+    if (Imm16::IsInSignedRange(-imm.value)) {
+        as_addiu(rd, rs, -imm.value);
+    } else {
+        ma_li(ScratchRegister, imm);
+        as_subu(rd, rs, ScratchRegister);
+    }
+}
+
+void
+MacroAssemblerMIPSShared::ma_subu(Register rd, Imm32 imm)
+{
+    ma_subu(rd, rd, imm);
+}
+
+void
+MacroAssemblerMIPSShared::ma_subTestOverflow(Register rd, Register rs, Imm32 imm, Label* overflow)
+{
+    if (imm.value != INT32_MIN) {
+        asMasm().ma_addTestOverflow(rd, rs, Imm32(-imm.value), overflow);
+    } else {
+        ma_li(ScratchRegister, Imm32(imm.value));
+        asMasm().ma_subTestOverflow(rd, rs, ScratchRegister, overflow);
+    }
+}
+
+void
+MacroAssemblerMIPSShared::ma_mult(Register rs, Imm32 imm)
+{
+    ma_li(ScratchRegister, imm);
+    as_mult(rs, ScratchRegister);
+}
+
+void
+MacroAssemblerMIPSShared::ma_mul_branch_overflow(Register rd, Register rs, Register rt, Label* overflow)
+{
+    as_mult(rs, rt);
+    as_mflo(rd);
+    as_sra(ScratchRegister, rd, 31);
+    as_mfhi(SecondScratchReg);
+    ma_b(ScratchRegister, SecondScratchReg, overflow, Assembler::NotEqual);
+}
+
+void
+MacroAssemblerMIPSShared::ma_mul_branch_overflow(Register rd, Register rs, Imm32 imm, Label* overflow)
+{
+    ma_li(ScratchRegister, imm);
+    ma_mul_branch_overflow(rd, rs, ScratchRegister, overflow);
+}
+
+void
+MacroAssemblerMIPSShared::ma_div_branch_overflow(Register rd, Register rs, Register rt, Label* overflow)
+{
+    as_div(rs, rt);
+    as_mflo(rd);
+    as_mfhi(ScratchRegister);
+    ma_b(ScratchRegister, ScratchRegister, overflow, Assembler::NonZero);
+}
+
+void
+MacroAssemblerMIPSShared::ma_div_branch_overflow(Register rd, Register rs, Imm32 imm, Label* overflow)
+{
+    ma_li(ScratchRegister, imm);
+    ma_div_branch_overflow(rd, rs, ScratchRegister, overflow);
+}
+
+void
+MacroAssemblerMIPSShared::ma_mod_mask(Register src, Register dest, Register hold, Register remain,
+                                      int32_t shift, Label* negZero)
+{
+    // MATH:
+    // We wish to compute x % (1<<y) - 1 for a known constant, y.
+    // First, let b = (1<<y) and C = (1<<y)-1, then think of the 32 bit
+    // dividend as a number in base b, namely
+    // c_0*1 + c_1*b + c_2*b^2 ... c_n*b^n
+    // now, since both addition and multiplication commute with modulus,
+    // x % C == (c_0 + c_1*b + ... + c_n*b^n) % C ==
+    // (c_0 % C) + (c_1%C) * (b % C) + (c_2 % C) * (b^2 % C)...
+    // now, since b == C + 1, b % C == 1, and b^n % C == 1
+    // this means that the whole thing simplifies to:
+    // c_0 + c_1 + c_2 ... c_n % C
+    // each c_n can easily be computed by a shift/bitextract, and the modulus
+    // can be maintained by simply subtracting by C whenever the number gets
+    // over C.
+    int32_t mask = (1 << shift) - 1;
+    Label head, negative, sumSigned, done;
+
+    // hold holds -1 if the value was negative, 1 otherwise.
+    // remain holds the remaining bits that have not been processed
+    // SecondScratchReg serves as a temporary location to store extracted bits
+    // into as well as holding the trial subtraction as a temp value dest is
+    // the accumulator (and holds the final result)
+
+    // move the whole value into the remain.
+    ma_move(remain, src);
+    // Zero out the dest.
+    ma_li(dest, Imm32(0));
+    // Set the hold appropriately.
+    ma_b(remain, remain, &negative, Signed, ShortJump);
+    ma_li(hold, Imm32(1));
+    ma_b(&head, ShortJump);
+
+    bind(&negative);
+    ma_li(hold, Imm32(-1));
+    ma_negu(remain, remain);
+
+    // Begin the main loop.
+    bind(&head);
+
+    // Extract the bottom bits into SecondScratchReg.
+    ma_and(SecondScratchReg, remain, Imm32(mask));
+    // Add those bits to the accumulator.
+    as_addu(dest, dest, SecondScratchReg);
+    // Do a trial subtraction
+    ma_subu(SecondScratchReg, dest, Imm32(mask));
+    // If (sum - C) > 0, store sum - C back into sum, thus performing a
+    // modulus.
+    ma_b(SecondScratchReg, SecondScratchReg, &sumSigned, Signed, ShortJump);
+    ma_move(dest, SecondScratchReg);
+    bind(&sumSigned);
+    // Get rid of the bits that we extracted before.
+    as_srl(remain, remain, shift);
+    // If the shift produced zero, finish, otherwise, continue in the loop.
+    ma_b(remain, remain, &head, NonZero, ShortJump);
+    // Check the hold to see if we need to negate the result.
+    ma_b(hold, hold, &done, NotSigned, ShortJump);
+
+    // If the hold was non-zero, negate the result to be in line with
+    // what JS wants
+    if (negZero != nullptr) {
+        // Jump out in case of negative zero.
+        ma_b(hold, hold, negZero, Zero);
+        ma_negu(dest, dest);
+    } else {
+        ma_negu(dest, dest);
+    }
+
+    bind(&done);
+}
+
+// Memory.
+
+void
+MacroAssemblerMIPSShared::ma_load(Register dest, const BaseIndex& src,
+                                  LoadStoreSize size, LoadStoreExtension extension)
+{
+    asMasm().computeScaledAddress(src, SecondScratchReg);
+    asMasm().ma_load(dest, Address(SecondScratchReg, src.offset), size, extension);
+}
+
+void
+MacroAssemblerMIPSShared::ma_store(Register data, const BaseIndex& dest,
+                                   LoadStoreSize size, LoadStoreExtension extension)
+{
+    asMasm().computeScaledAddress(dest, SecondScratchReg);
+    asMasm().ma_store(data, Address(SecondScratchReg, dest.offset), size, extension);
+}
+
+void
+MacroAssemblerMIPSShared::ma_store(Imm32 imm, const BaseIndex& dest,
+                                   LoadStoreSize size, LoadStoreExtension extension)
+{
+    // Make sure that SecondScratchReg contains absolute address so that
+    // offset is 0.
+    asMasm().computeEffectiveAddress(dest, SecondScratchReg);
+
+    // Scrach register is free now, use it for loading imm value
+    ma_li(ScratchRegister, imm);
+
+    // with offset=0 ScratchRegister will not be used in ma_store()
+    // so we can use it as a parameter here
+    asMasm().ma_store(ScratchRegister, Address(SecondScratchReg, 0), size, extension);
+}
+
+// Branches when done from within mips-specific code.
+void
+MacroAssemblerMIPSShared::ma_b(Register lhs, Register rhs, Label* label, Condition c, JumpKind jumpKind)
+{
+    switch (c) {
+      case Equal :
+      case NotEqual:
+        asMasm().branchWithCode(getBranchCode(lhs, rhs, c), label, jumpKind);
+        break;
+      case Always:
+        ma_b(label, jumpKind);
+        break;
+      case Zero:
+      case NonZero:
+      case Signed:
+      case NotSigned:
+        MOZ_ASSERT(lhs == rhs);
+        asMasm().branchWithCode(getBranchCode(lhs, c), label, jumpKind);
+        break;
+      default:
+        Condition cond = ma_cmp(ScratchRegister, lhs, rhs, c);
+        asMasm().branchWithCode(getBranchCode(ScratchRegister, cond), label, jumpKind);
+        break;
+    }
+}
+
+void
+MacroAssemblerMIPSShared::ma_b(Register lhs, Imm32 imm, Label* label, Condition c, JumpKind jumpKind)
+{
+    MOZ_ASSERT(c != Overflow);
+    if (imm.value == 0) {
+        if (c == Always || c == AboveOrEqual)
+            ma_b(label, jumpKind);
+        else if (c == Below)
+            ; // This condition is always false. No branch required.
+        else
+            asMasm().branchWithCode(getBranchCode(lhs, c), label, jumpKind);
+    } else {
+        MOZ_ASSERT(lhs != ScratchRegister);
+        ma_li(ScratchRegister, imm);
+        ma_b(lhs, ScratchRegister, label, c, jumpKind);
+    }
+}
+
+void
+MacroAssemblerMIPSShared::ma_b(Register lhs, ImmPtr imm, Label* l, Condition c, JumpKind jumpKind)
+{
+    asMasm().ma_b(lhs, ImmWord(uintptr_t(imm.value)), l, c, jumpKind);
+}
+
+void
+MacroAssemblerMIPSShared::ma_b(Label* label, JumpKind jumpKind)
+{
+    asMasm().branchWithCode(getBranchCode(BranchIsJump), label, jumpKind);
+}
+
+Assembler::Condition
+MacroAssemblerMIPSShared::ma_cmp(Register scratch, Register lhs, Register rhs, Condition c)
+{
+    switch (c) {
+      case Above:
+        // bgtu s,t,label =>
+        //   sltu at,t,s
+        //   bne at,$zero,offs
+        as_sltu(scratch, rhs, lhs);
+        return NotEqual;
+      case AboveOrEqual:
+        // bgeu s,t,label =>
+        //   sltu at,s,t
+        //   beq at,$zero,offs
+        as_sltu(scratch, lhs, rhs);
+        return Equal;
+      case Below:
+        // bltu s,t,label =>
+        //   sltu at,s,t
+        //   bne at,$zero,offs
+        as_sltu(scratch, lhs, rhs);
+        return NotEqual;
+      case BelowOrEqual:
+        // bleu s,t,label =>
+        //   sltu at,t,s
+        //   beq at,$zero,offs
+        as_sltu(scratch, rhs, lhs);
+        return Equal;
+      case GreaterThan:
+        // bgt s,t,label =>
+        //   slt at,t,s
+        //   bne at,$zero,offs
+        as_slt(scratch, rhs, lhs);
+        return NotEqual;
+      case GreaterThanOrEqual:
+        // bge s,t,label =>
+        //   slt at,s,t
+        //   beq at,$zero,offs
+        as_slt(scratch, lhs, rhs);
+        return Equal;
+      case LessThan:
+        // blt s,t,label =>
+        //   slt at,s,t
+        //   bne at,$zero,offs
+        as_slt(scratch, lhs, rhs);
+        return NotEqual;
+      case LessThanOrEqual:
+        // ble s,t,label =>
+        //   slt at,t,s
+        //   beq at,$zero,offs
+        as_slt(scratch, rhs, lhs);
+        return Equal;
+      case Equal :
+      case NotEqual:
+      case Zero:
+      case NonZero:
+      case Always:
+      case Signed:
+      case NotSigned:
+        MOZ_CRASH("There is a better way to compare for equality.");
+        break;
+      case Overflow:
+        MOZ_CRASH("Overflow condition not supported for MIPS.");
+        break;
+      default:
+        MOZ_CRASH("Invalid condition for branch.");
+    }
+    return Always;
+}
+
+void
+MacroAssemblerMIPSShared::ma_cmp_set(Register rd, Register rs, Register rt, Condition c)
+{
+    switch (c) {
+      case Equal :
+        // seq d,s,t =>
+        //   xor d,s,t
+        //   sltiu d,d,1
+        as_xor(rd, rs, rt);
+        as_sltiu(rd, rd, 1);
+        break;
+      case NotEqual:
+        // sne d,s,t =>
+        //   xor d,s,t
+        //   sltu d,$zero,d
+        as_xor(rd, rs, rt);
+        as_sltu(rd, zero, rd);
+        break;
+      case Above:
+        // sgtu d,s,t =>
+        //   sltu d,t,s
+        as_sltu(rd, rt, rs);
+        break;
+      case AboveOrEqual:
+        // sgeu d,s,t =>
+        //   sltu d,s,t
+        //   xori d,d,1
+        as_sltu(rd, rs, rt);
+        as_xori(rd, rd, 1);
+        break;
+      case Below:
+        // sltu d,s,t
+        as_sltu(rd, rs, rt);
+        break;
+      case BelowOrEqual:
+        // sleu d,s,t =>
+        //   sltu d,t,s
+        //   xori d,d,1
+        as_sltu(rd, rt, rs);
+        as_xori(rd, rd, 1);
+        break;
+      case GreaterThan:
+        // sgt d,s,t =>
+        //   slt d,t,s
+        as_slt(rd, rt, rs);
+        break;
+      case GreaterThanOrEqual:
+        // sge d,s,t =>
+        //   slt d,s,t
+        //   xori d,d,1
+        as_slt(rd, rs, rt);
+        as_xori(rd, rd, 1);
+        break;
+      case LessThan:
+        // slt d,s,t
+        as_slt(rd, rs, rt);
+        break;
+      case LessThanOrEqual:
+        // sle d,s,t =>
+        //   slt d,t,s
+        //   xori d,d,1
+        as_slt(rd, rt, rs);
+        as_xori(rd, rd, 1);
+        break;
+      case Zero:
+        MOZ_ASSERT(rs == rt);
+        // seq d,s,$zero =>
+        //   xor d,s,$zero
+        //   sltiu d,d,1
+        as_xor(rd, rs, zero);
+        as_sltiu(rd, rd, 1);
+        break;
+      case NonZero:
+        // sne d,s,$zero =>
+        //   xor d,s,$zero
+        //   sltu d,$zero,d
+        as_xor(rd, rs, zero);
+        as_sltu(rd, zero, rd);
+        break;
+      case Signed:
+        as_slt(rd, rs, zero);
+        break;
+      case NotSigned:
+        // sge d,s,$zero =>
+        //   slt d,s,$zero
+        //   xori d,d,1
+        as_slt(rd, rs, zero);
+        as_xori(rd, rd, 1);
+        break;
+      default:
+        MOZ_CRASH("Invalid condition for ma_cmp_set.");
+    }
+}
+
+void
+MacroAssemblerMIPSShared::compareFloatingPoint(FloatFormat fmt, FloatRegister lhs, FloatRegister rhs,
+                                               DoubleCondition c, FloatTestKind* testKind,
+                                               FPConditionBit fcc)
+{
+    switch (c) {
+      case DoubleOrdered:
+        as_cun(fmt, lhs, rhs, fcc);
+        *testKind = TestForFalse;
+        break;
+      case DoubleEqual:
+        as_ceq(fmt, lhs, rhs, fcc);
+        *testKind = TestForTrue;
+        break;
+      case DoubleNotEqual:
+        as_cueq(fmt, lhs, rhs, fcc);
+        *testKind = TestForFalse;
+        break;
+      case DoubleGreaterThan:
+        as_colt(fmt, rhs, lhs, fcc);
+        *testKind = TestForTrue;
+        break;
+      case DoubleGreaterThanOrEqual:
+        as_cole(fmt, rhs, lhs, fcc);
+        *testKind = TestForTrue;
+        break;
+      case DoubleLessThan:
+        as_colt(fmt, lhs, rhs, fcc);
+        *testKind = TestForTrue;
+        break;
+      case DoubleLessThanOrEqual:
+        as_cole(fmt, lhs, rhs, fcc);
+        *testKind = TestForTrue;
+        break;
+      case DoubleUnordered:
+        as_cun(fmt, lhs, rhs, fcc);
+        *testKind = TestForTrue;
+        break;
+      case DoubleEqualOrUnordered:
+        as_cueq(fmt, lhs, rhs, fcc);
+        *testKind = TestForTrue;
+        break;
+      case DoubleNotEqualOrUnordered:
+        as_ceq(fmt, lhs, rhs, fcc);
+        *testKind = TestForFalse;
+        break;
+      case DoubleGreaterThanOrUnordered:
+        as_cult(fmt, rhs, lhs, fcc);
+        *testKind = TestForTrue;
+        break;
+      case DoubleGreaterThanOrEqualOrUnordered:
+        as_cule(fmt, rhs, lhs, fcc);
+        *testKind = TestForTrue;
+        break;
+      case DoubleLessThanOrUnordered:
+        as_cult(fmt, lhs, rhs, fcc);
+        *testKind = TestForTrue;
+        break;
+      case DoubleLessThanOrEqualOrUnordered:
+        as_cule(fmt, lhs, rhs, fcc);
+        *testKind = TestForTrue;
+        break;
+      default:
+        MOZ_CRASH("Invalid DoubleCondition.");
+    }
+}
+
+void
+MacroAssemblerMIPSShared::ma_cmp_set_double(Register dest, FloatRegister lhs, FloatRegister rhs,
+                                            DoubleCondition c)
+{
+    ma_li(dest, Imm32(0));
+    ma_li(ScratchRegister, Imm32(1));
+
+    FloatTestKind moveCondition;
+    compareFloatingPoint(DoubleFloat, lhs, rhs, c, &moveCondition);
+
+    if (moveCondition == TestForTrue)
+        as_movt(dest, ScratchRegister);
+    else
+        as_movf(dest, ScratchRegister);
+}
+
+void
+MacroAssemblerMIPSShared::ma_cmp_set_float32(Register dest, FloatRegister lhs, FloatRegister rhs,
+                                             DoubleCondition c)
+{
+    ma_li(dest, Imm32(0));
+    ma_li(ScratchRegister, Imm32(1));
+
+    FloatTestKind moveCondition;
+    compareFloatingPoint(SingleFloat, lhs, rhs, c, &moveCondition);
+
+    if (moveCondition == TestForTrue)
+        as_movt(dest, ScratchRegister);
+    else
+        as_movf(dest, ScratchRegister);
+}
+
+void
+MacroAssemblerMIPSShared::ma_cmp_set(Register rd, Register rs, Imm32 imm, Condition c)
+{
+    ma_li(ScratchRegister, imm);
+    ma_cmp_set(rd, rs, ScratchRegister, c);
+}
+
+// fp instructions
+void
+MacroAssemblerMIPSShared::ma_lis(FloatRegister dest, float value)
+{
+    Imm32 imm(mozilla::BitwiseCast<uint32_t>(value));
+
+    ma_li(ScratchRegister, imm);
+    moveToFloat32(ScratchRegister, dest);
+}
+
+void
+MacroAssemblerMIPSShared::ma_liNegZero(FloatRegister dest)
+{
+    moveToDoubleLo(zero, dest);
+    ma_li(ScratchRegister, Imm32(INT_MIN));
+    asMasm().moveToDoubleHi(ScratchRegister, dest);
+}
+
+void
+MacroAssemblerMIPSShared::ma_sd(FloatRegister ft, BaseIndex address)
+{
+    asMasm().computeScaledAddress(address, SecondScratchReg);
+    asMasm().ma_sd(ft, Address(SecondScratchReg, address.offset));
+}
+
+void
+MacroAssemblerMIPSShared::ma_ss(FloatRegister ft, BaseIndex address)
+{
+    asMasm().computeScaledAddress(address, SecondScratchReg);
+    asMasm().ma_ss(ft, Address(SecondScratchReg, address.offset));
+}
+
+void
+MacroAssemblerMIPSShared::ma_bc1s(FloatRegister lhs, FloatRegister rhs, Label* label,
+                                  DoubleCondition c, JumpKind jumpKind, FPConditionBit fcc)
+{
+    FloatTestKind testKind;
+    compareFloatingPoint(SingleFloat, lhs, rhs, c, &testKind, fcc);
+    asMasm().branchWithCode(getBranchCode(testKind, fcc), label, jumpKind);
+}
+
+void
+MacroAssemblerMIPSShared::ma_bc1d(FloatRegister lhs, FloatRegister rhs, Label* label,
+                                  DoubleCondition c, JumpKind jumpKind, FPConditionBit fcc)
+{
+    FloatTestKind testKind;
+    compareFloatingPoint(DoubleFloat, lhs, rhs, c, &testKind, fcc);
+    asMasm().branchWithCode(getBranchCode(testKind, fcc), label, jumpKind);
+}
+
+void
+MacroAssemblerMIPSShared::ma_call(ImmPtr dest)
+{
+    asMasm().ma_liPatchable(CallReg, dest);
+    as_jalr(CallReg);
+    as_nop();
+}
+
+void
+MacroAssemblerMIPSShared::ma_jump(ImmPtr dest)
+{
+    asMasm().ma_liPatchable(ScratchRegister, dest);
+    as_jr(ScratchRegister);
+    as_nop();
+}
+
+MacroAssembler&
+MacroAssemblerMIPSShared::asMasm()
+{
+    return *static_cast<MacroAssembler*>(this);
+}
+
+const MacroAssembler&
+MacroAssemblerMIPSShared::asMasm() const
+{
+    return *static_cast<const MacroAssembler*>(this);
+}
diff --git a/js/src/jit/mips-shared/MacroAssembler-mips-shared.h b/js/src/jit/mips-shared/MacroAssembler-mips-shared.h
new file mode 100644
index 00000000000..359b247cd54
--- /dev/null
+++ b/js/src/jit/mips-shared/MacroAssembler-mips-shared.h
@@ -0,0 +1,185 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef jit_mips_shared_MacroAssembler_mips_shared_h
+#define jit_mips_shared_MacroAssembler_mips_shared_h
+
+#if defined(JS_CODEGEN_MIPS32)
+# include "jit/mips32/Assembler-mips32.h"
+#endif
+
+namespace js {
+namespace jit {
+
+enum LoadStoreSize
+{
+    SizeByte = 8,
+    SizeHalfWord = 16,
+    SizeWord = 32,
+    SizeDouble = 64
+};
+
+enum LoadStoreExtension
+{
+    ZeroExtend = 0,
+    SignExtend = 1
+};
+
+enum JumpKind
+{
+    LongJump = 0,
+    ShortJump = 1
+};
+
+enum DelaySlotFill
+{
+    DontFillDelaySlot = 0,
+    FillDelaySlot = 1
+};
+
+static Register CallReg = t9;
+
+class MacroAssemblerMIPSShared : public Assembler
+{
+  protected:
+    // Perform a downcast. Should be removed by Bug 996602.
+    MacroAssembler& asMasm();
+    const MacroAssembler& asMasm() const;
+
+    Condition ma_cmp(Register rd, Register lhs, Register rhs, Condition c);
+
+    void compareFloatingPoint(FloatFormat fmt, FloatRegister lhs, FloatRegister rhs,
+                              DoubleCondition c, FloatTestKind* testKind,
+                              FPConditionBit fcc = FCC0);
+
+  public:
+    void ma_move(Register rd, Register rs);
+
+    void ma_li(Register dest, ImmGCPtr ptr);
+
+    void ma_li(Register dest, Imm32 imm);
+
+    // Shift operations
+    void ma_sll(Register rd, Register rt, Imm32 shift);
+    void ma_srl(Register rd, Register rt, Imm32 shift);
+    void ma_sra(Register rd, Register rt, Imm32 shift);
+    void ma_ror(Register rd, Register rt, Imm32 shift);
+    void ma_rol(Register rd, Register rt, Imm32 shift);
+
+    void ma_sll(Register rd, Register rt, Register shift);
+    void ma_srl(Register rd, Register rt, Register shift);
+    void ma_sra(Register rd, Register rt, Register shift);
+    void ma_ror(Register rd, Register rt, Register shift);
+    void ma_rol(Register rd, Register rt, Register shift);
+
+    // Negate
+    void ma_negu(Register rd, Register rs);
+
+    void ma_not(Register rd, Register rs);
+
+    // and
+    void ma_and(Register rd, Register rs);
+    void ma_and(Register rd, Imm32 imm);
+    void ma_and(Register rd, Register rs, Imm32 imm);
+
+    // or
+    void ma_or(Register rd, Register rs);
+    void ma_or(Register rd, Imm32 imm);
+    void ma_or(Register rd, Register rs, Imm32 imm);
+
+    // xor
+    void ma_xor(Register rd, Register rs);
+    void ma_xor(Register rd, Imm32 imm);
+    void ma_xor(Register rd, Register rs, Imm32 imm);
+
+    // load
+    void ma_load(Register dest, const BaseIndex& src, LoadStoreSize size = SizeWord,
+                 LoadStoreExtension extension = SignExtend);
+
+    // store
+    void ma_store(Register data, const BaseIndex& dest, LoadStoreSize size = SizeWord,
+                  LoadStoreExtension extension = SignExtend);
+    void ma_store(Imm32 imm, const BaseIndex& dest, LoadStoreSize size = SizeWord,
+                  LoadStoreExtension extension = SignExtend);
+
+    // arithmetic based ops
+    // add
+    void ma_addu(Register rd, Register rs, Imm32 imm);
+    void ma_addu(Register rd, Register rs);
+    void ma_addu(Register rd, Imm32 imm);
+
+    // subtract
+    void ma_subu(Register rd, Register rs, Imm32 imm);
+    void ma_subu(Register rd, Imm32 imm);
+    void ma_subTestOverflow(Register rd, Register rs, Imm32 imm, Label* overflow);
+
+    // multiplies.  For now, there are only few that we care about.
+    void ma_mult(Register rs, Imm32 imm);
+    void ma_mul_branch_overflow(Register rd, Register rs, Register rt, Label* overflow);
+    void ma_mul_branch_overflow(Register rd, Register rs, Imm32 imm, Label* overflow);
+
+    // divisions
+    void ma_div_branch_overflow(Register rd, Register rs, Register rt, Label* overflow);
+    void ma_div_branch_overflow(Register rd, Register rs, Imm32 imm, Label* overflow);
+
+    // fast mod, uses scratch registers, and thus needs to be in the assembler
+    // implicitly assumes that we can overwrite dest at the beginning of the sequence
+    void ma_mod_mask(Register src, Register dest, Register hold, Register remain,
+                     int32_t shift, Label* negZero = nullptr);
+
+    // branches when done from within mips-specific code
+    void ma_b(Register lhs, Register rhs, Label* l, Condition c, JumpKind jumpKind = LongJump);
+    void ma_b(Register lhs, Imm32 imm, Label* l, Condition c, JumpKind jumpKind = LongJump);
+    void ma_b(Register lhs, ImmPtr imm, Label* l, Condition c, JumpKind jumpKind = LongJump);
+    void ma_b(Register lhs, ImmGCPtr imm, Label* l, Condition c, JumpKind jumpKind = LongJump) {
+        MOZ_ASSERT(lhs != ScratchRegister);
+        ma_li(ScratchRegister, imm);
+        ma_b(lhs, ScratchRegister, l, c, jumpKind);
+    }
+
+    void ma_b(Label* l, JumpKind jumpKind = LongJump);
+
+    // fp instructions
+    void ma_lis(FloatRegister dest, float value);
+    void ma_liNegZero(FloatRegister dest);
+
+    void ma_sd(FloatRegister fd, BaseIndex address);
+    void ma_ss(FloatRegister fd, BaseIndex address);
+
+    //FP branches
+    void ma_bc1s(FloatRegister lhs, FloatRegister rhs, Label* label, DoubleCondition c,
+                 JumpKind jumpKind = LongJump, FPConditionBit fcc = FCC0);
+    void ma_bc1d(FloatRegister lhs, FloatRegister rhs, Label* label, DoubleCondition c,
+                 JumpKind jumpKind = LongJump, FPConditionBit fcc = FCC0);
+
+    void ma_call(ImmPtr dest);
+
+    void ma_jump(ImmPtr dest);
+
+    void ma_cmp_set(Register dst, Register lhs, Register rhs, Condition c);
+    void ma_cmp_set(Register dst, Register lhs, Imm32 imm, Condition c);
+    void ma_cmp_set_double(Register dst, FloatRegister lhs, FloatRegister rhs, DoubleCondition c);
+    void ma_cmp_set_float32(Register dst, FloatRegister lhs, FloatRegister rhs, DoubleCondition c);
+
+    void moveToDoubleLo(Register src, FloatRegister dest) {
+        as_mtc1(src, dest);
+    }
+    void moveFromDoubleLo(FloatRegister src, Register dest) {
+        as_mfc1(dest, src);
+    }
+
+    void moveToFloat32(Register src, FloatRegister dest) {
+        as_mtc1(src, dest);
+    }
+    void moveFromFloat32(FloatRegister src, Register dest) {
+        as_mfc1(dest, src);
+    }
+};
+
+} // namespace jit
+} // namespace js
+
+#endif /* jit_mips_shared_MacroAssembler_mips_shared_h */
diff --git a/js/src/jit/mips32/Bailouts-mips32.cpp b/js/src/jit/mips32/Bailouts-mips32.cpp
index c8856fdc6d8..1b92d729c93 100644
--- a/js/src/jit/mips32/Bailouts-mips32.cpp
+++ b/js/src/jit/mips32/Bailouts-mips32.cpp
@@ -4,11 +4,11 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include "jit/mips32/Bailouts-mips32.h"
+
 #include "jscntxt.h"
 #include "jscompartment.h"
 
-#include "jit/mips-shared/Bailouts-mips-shared.h"
-
 using namespace js;
 using namespace js::jit;
 
diff --git a/js/src/jit/mips-shared/Bailouts-mips-shared.h b/js/src/jit/mips32/Bailouts-mips32.h
similarity index 93%
rename from js/src/jit/mips-shared/Bailouts-mips-shared.h
rename to js/src/jit/mips32/Bailouts-mips32.h
index 575d13def21..0c4d7f31327 100644
--- a/js/src/jit/mips-shared/Bailouts-mips-shared.h
+++ b/js/src/jit/mips32/Bailouts-mips32.h
@@ -4,8 +4,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#ifndef jit_mips_shared_Bailouts_mips_shared_h
-#define jit_mips_shared_Bailouts_mips_shared_h
+#ifndef jit_mips32_Bailouts_mips32_h
+#define jit_mips32_Bailouts_mips32_h
 
 #include "jit/Bailouts.h"
 #include "jit/JitCompartment.h"
@@ -74,4 +74,4 @@ class BailoutStack
 } // namespace jit
 } // namespace js
 
-#endif /* jit_mips_shared_Bailouts_mips_shared_h */
+#endif /* jit_mips32_Bailouts_mips32_h */
diff --git a/js/src/jit/mips32/MacroAssembler-mips32.cpp b/js/src/jit/mips32/MacroAssembler-mips32.cpp
index f83f8d38790..105d2dbaf2f 100644
--- a/js/src/jit/mips32/MacroAssembler-mips32.cpp
+++ b/js/src/jit/mips32/MacroAssembler-mips32.cpp
@@ -311,19 +311,6 @@ MacroAssemblerMIPSCompat::inc64(AbsoluteAddress dest)
     as_sw(SecondScratchReg, ScratchRegister, 4);
 }
 
-void
-MacroAssemblerMIPS::ma_move(Register rd, Register rs)
-{
-    as_or(rd, rs, zero);
-}
-
-void
-MacroAssemblerMIPS::ma_li(Register dest, ImmGCPtr ptr)
-{
-    writeDataRelocation(ptr);
-    ma_liPatchable(dest, ImmPtr(ptr.value));
-}
-
 void
 MacroAssemblerMIPS::ma_li(Register dest, AbsoluteLabel* label)
 {
@@ -335,21 +322,6 @@ MacroAssemblerMIPS::ma_li(Register dest, AbsoluteLabel* label)
     label->setPrev(bo.getOffset());
 }
 
-void
-MacroAssemblerMIPS::ma_li(Register dest, Imm32 imm)
-{
-    if (Imm16::IsInSignedRange(imm.value)) {
-        as_addiu(dest, zero, imm.value);
-    } else if (Imm16::IsInUnsignedRange(imm.value)) {
-        as_ori(dest, zero, Imm16::Lower(imm).encode());
-    } else if (Imm16::Lower(imm).encode() == 0) {
-        as_lui(dest, Imm16::Upper(imm).encode());
-    } else {
-        as_lui(dest, Imm16::Upper(imm).encode());
-        as_ori(dest, dest, Imm16::Lower(imm).encode());
-    }
-}
-
 void
 MacroAssemblerMIPS::ma_li(Register dest, ImmWord imm)
 {
@@ -379,177 +351,9 @@ MacroAssemblerMIPS::ma_liPatchable(Register dest, ImmWord imm)
     ma_liPatchable(dest, Imm32(int32_t(imm.value)));
 }
 
-// Shifts
-void
-MacroAssemblerMIPS::ma_sll(Register rd, Register rt, Imm32 shift)
-{
-    as_sll(rd, rt, shift.value % 32);
-}
-void
-MacroAssemblerMIPS::ma_srl(Register rd, Register rt, Imm32 shift)
-{
-    as_srl(rd, rt, shift.value % 32);
-}
-
-void
-MacroAssemblerMIPS::ma_sra(Register rd, Register rt, Imm32 shift)
-{
-    as_sra(rd, rt, shift.value % 32);
-}
-
-void
-MacroAssemblerMIPS::ma_ror(Register rd, Register rt, Imm32 shift)
-{
-    as_rotr(rd, rt, shift.value % 32);
-}
-
-void
-MacroAssemblerMIPS::ma_rol(Register rd, Register rt, Imm32 shift)
-{
-    as_rotr(rd, rt, 32 - (shift.value % 32));
-}
-
-void
-MacroAssemblerMIPS::ma_sll(Register rd, Register rt, Register shift)
-{
-    as_sllv(rd, rt, shift);
-}
-
-void
-MacroAssemblerMIPS::ma_srl(Register rd, Register rt, Register shift)
-{
-    as_srlv(rd, rt, shift);
-}
-
-void
-MacroAssemblerMIPS::ma_sra(Register rd, Register rt, Register shift)
-{
-    as_srav(rd, rt, shift);
-}
-
-void
-MacroAssemblerMIPS::ma_ror(Register rd, Register rt, Register shift)
-{
-    as_rotrv(rd, rt, shift);
-}
-
-void
-MacroAssemblerMIPS::ma_rol(Register rd, Register rt, Register shift)
-{
-    ma_negu(ScratchRegister, shift);
-    as_rotrv(rd, rt, ScratchRegister);
-}
-
-void
-MacroAssemblerMIPS::ma_negu(Register rd, Register rs)
-{
-    as_subu(rd, zero, rs);
-}
-
-void
-MacroAssemblerMIPS::ma_not(Register rd, Register rs)
-{
-    as_nor(rd, rs, zero);
-}
-
-// And.
-void
-MacroAssemblerMIPS::ma_and(Register rd, Register rs)
-{
-    as_and(rd, rd, rs);
-}
-
-void
-MacroAssemblerMIPS::ma_and(Register rd, Imm32 imm)
-{
-    ma_and(rd, rd, imm);
-}
-
-void
-MacroAssemblerMIPS::ma_and(Register rd, Register rs, Imm32 imm)
-{
-    if (Imm16::IsInUnsignedRange(imm.value)) {
-        as_andi(rd, rs, imm.value);
-    } else {
-        ma_li(ScratchRegister, imm);
-        as_and(rd, rs, ScratchRegister);
-    }
-}
-
-// Or.
-void
-MacroAssemblerMIPS::ma_or(Register rd, Register rs)
-{
-    as_or(rd, rd, rs);
-}
-
-void
-MacroAssemblerMIPS::ma_or(Register rd, Imm32 imm)
-{
-    ma_or(rd, rd, imm);
-}
-
-void
-MacroAssemblerMIPS::ma_or(Register rd, Register rs, Imm32 imm)
-{
-    if (Imm16::IsInUnsignedRange(imm.value)) {
-        as_ori(rd, rs, imm.value);
-    } else {
-        ma_li(ScratchRegister, imm);
-        as_or(rd, rs, ScratchRegister);
-    }
-}
-
-// xor
-void
-MacroAssemblerMIPS::ma_xor(Register rd, Register rs)
-{
-    as_xor(rd, rd, rs);
-}
-
-void
-MacroAssemblerMIPS::ma_xor(Register rd, Imm32 imm)
-{
-    ma_xor(rd, rd, imm);
-}
-
-void
-MacroAssemblerMIPS::ma_xor(Register rd, Register rs, Imm32 imm)
-{
-    if (Imm16::IsInUnsignedRange(imm.value)) {
-        as_xori(rd, rs, imm.value);
-    } else {
-        ma_li(ScratchRegister, imm);
-        as_xor(rd, rs, ScratchRegister);
-    }
-}
-
 // Arithmetic-based ops.
 
 // Add.
-void
-MacroAssemblerMIPS::ma_addu(Register rd, Register rs, Imm32 imm)
-{
-    if (Imm16::IsInSignedRange(imm.value)) {
-        as_addiu(rd, rs, imm.value);
-    } else {
-        ma_li(ScratchRegister, imm);
-        as_addu(rd, rs, ScratchRegister);
-    }
-}
-
-void
-MacroAssemblerMIPS::ma_addu(Register rd, Register rs)
-{
-    as_addu(rd, rd, rs);
-}
-
-void
-MacroAssemblerMIPS::ma_addu(Register rd, Imm32 imm)
-{
-    ma_addu(rd, rd, imm);
-}
-
 void
 MacroAssemblerMIPS::ma_addTestOverflow(Register rd, Register rs, Register rt, Label* overflow)
 {
@@ -591,23 +395,6 @@ MacroAssemblerMIPS::ma_addTestOverflow(Register rd, Register rs, Imm32 imm, Labe
 }
 
 // Subtract.
-void
-MacroAssemblerMIPS::ma_subu(Register rd, Register rs, Imm32 imm)
-{
-    if (Imm16::IsInSignedRange(-imm.value)) {
-        as_addiu(rd, rs, -imm.value);
-    } else {
-        ma_li(ScratchRegister, imm);
-        as_subu(rd, rs, ScratchRegister);
-    }
-}
-
-void
-MacroAssemblerMIPS::ma_subu(Register rd, Imm32 imm)
-{
-    ma_subu(rd, rd, imm);
-}
-
 void
 MacroAssemblerMIPS::ma_subTestOverflow(Register rd, Register rs, Register rt, Label* overflow)
 {
@@ -626,131 +413,6 @@ MacroAssemblerMIPS::ma_subTestOverflow(Register rd, Register rs, Register rt, La
     bind(&goodSubtraction);
 }
 
-void
-MacroAssemblerMIPS::ma_subTestOverflow(Register rd, Register rs, Imm32 imm, Label* overflow)
-{
-    if (imm.value != INT32_MIN) {
-        ma_addTestOverflow(rd, rs, Imm32(-imm.value), overflow);
-    } else {
-        ma_li(ScratchRegister, Imm32(imm.value));
-        ma_subTestOverflow(rd, rs, ScratchRegister, overflow);
-    }
-}
-
-void
-MacroAssemblerMIPS::ma_mult(Register rs, Imm32 imm)
-{
-    ma_li(ScratchRegister, imm);
-    as_mult(rs, ScratchRegister);
-}
-
-void
-MacroAssemblerMIPS::ma_mul_branch_overflow(Register rd, Register rs, Register rt, Label* overflow)
-{
-    as_mult(rs, rt);
-    as_mflo(rd);
-    as_sra(ScratchRegister, rd, 31);
-    as_mfhi(SecondScratchReg);
-    ma_b(ScratchRegister, SecondScratchReg, overflow, Assembler::NotEqual);
-}
-
-void
-MacroAssemblerMIPS::ma_mul_branch_overflow(Register rd, Register rs, Imm32 imm, Label* overflow)
-{
-    ma_li(ScratchRegister, imm);
-    ma_mul_branch_overflow(rd, rs, ScratchRegister, overflow);
-}
-
-void
-MacroAssemblerMIPS::ma_div_branch_overflow(Register rd, Register rs, Register rt, Label* overflow)
-{
-    as_div(rs, rt);
-    as_mflo(rd);
-    as_mfhi(ScratchRegister);
-    ma_b(ScratchRegister, ScratchRegister, overflow, Assembler::NonZero);
-}
-
-void
-MacroAssemblerMIPS::ma_div_branch_overflow(Register rd, Register rs, Imm32 imm, Label* overflow)
-{
-    ma_li(ScratchRegister, imm);
-    ma_div_branch_overflow(rd, rs, ScratchRegister, overflow);
-}
-
-void
-MacroAssemblerMIPS::ma_mod_mask(Register src, Register dest, Register hold, Register remain,
-                                int32_t shift, Label* negZero)
-{
-    // MATH:
-    // We wish to compute x % (1<<y) - 1 for a known constant, y.
-    // First, let b = (1<<y) and C = (1<<y)-1, then think of the 32 bit
-    // dividend as a number in base b, namely
-    // c_0*1 + c_1*b + c_2*b^2 ... c_n*b^n
-    // now, since both addition and multiplication commute with modulus,
-    // x % C == (c_0 + c_1*b + ... + c_n*b^n) % C ==
-    // (c_0 % C) + (c_1%C) * (b % C) + (c_2 % C) * (b^2 % C)...
-    // now, since b == C + 1, b % C == 1, and b^n % C == 1
-    // this means that the whole thing simplifies to:
-    // c_0 + c_1 + c_2 ... c_n % C
-    // each c_n can easily be computed by a shift/bitextract, and the modulus
-    // can be maintained by simply subtracting by C whenever the number gets
-    // over C.
-    int32_t mask = (1 << shift) - 1;
-    Label head, negative, sumSigned, done;
-
-    // hold holds -1 if the value was negative, 1 otherwise.
-    // remain holds the remaining bits that have not been processed
-    // SecondScratchReg serves as a temporary location to store extracted bits
-    // into as well as holding the trial subtraction as a temp value dest is
-    // the accumulator (and holds the final result)
-
-    // move the whole value into the remain.
-    ma_move(remain, src);
-    // Zero out the dest.
-    ma_li(dest, Imm32(0));
-    // Set the hold appropriately.
-    ma_b(remain, remain, &negative, Signed, ShortJump);
-    ma_li(hold, Imm32(1));
-    ma_b(&head, ShortJump);
-
-    bind(&negative);
-    ma_li(hold, Imm32(-1));
-    ma_negu(remain, remain);
-
-    // Begin the main loop.
-    bind(&head);
-
-    // Extract the bottom bits into SecondScratchReg.
-    ma_and(SecondScratchReg, remain, Imm32(mask));
-    // Add those bits to the accumulator.
-    as_addu(dest, dest, SecondScratchReg);
-    // Do a trial subtraction
-    ma_subu(SecondScratchReg, dest, Imm32(mask));
-    // If (sum - C) > 0, store sum - C back into sum, thus performing a
-    // modulus.
-    ma_b(SecondScratchReg, SecondScratchReg, &sumSigned, Signed, ShortJump);
-    ma_move(dest, SecondScratchReg);
-    bind(&sumSigned);
-    // Get rid of the bits that we extracted before.
-    as_srl(remain, remain, shift);
-    // If the shift produced zero, finish, otherwise, continue in the loop.
-    ma_b(remain, remain, &head, NonZero, ShortJump);
-    // Check the hold to see if we need to negate the result.
-    ma_b(hold, hold, &done, NotSigned, ShortJump);
-
-    // If the hold was non-zero, negate the result to be in line with
-    // what JS wants
-    if (negZero != nullptr) {
-        // Jump out in case of negative zero.
-        ma_b(hold, hold, negZero, Zero);
-        ma_negu(dest, dest);
-    } else {
-        ma_negu(dest, dest);
-    }
-
-    bind(&done);
-}
-
 // Memory.
 
 void
@@ -790,14 +452,6 @@ MacroAssemblerMIPS::ma_load(Register dest, Address address,
     }
 }
 
-void
-MacroAssemblerMIPS::ma_load(Register dest, const BaseIndex& src,
-                            LoadStoreSize size, LoadStoreExtension extension)
-{
-    asMasm().computeScaledAddress(src, SecondScratchReg);
-    ma_load(dest, Address(SecondScratchReg, src.offset), size, extension);
-}
-
 void
 MacroAssemblerMIPS::ma_store(Register data, Address address, LoadStoreSize size,
                              LoadStoreExtension extension)
@@ -829,30 +483,6 @@ MacroAssemblerMIPS::ma_store(Register data, Address address, LoadStoreSize size,
     }
 }
 
-void
-MacroAssemblerMIPS::ma_store(Register data, const BaseIndex& dest,
-                             LoadStoreSize size, LoadStoreExtension extension)
-{
-    asMasm().computeScaledAddress(dest, SecondScratchReg);
-    ma_store(data, Address(SecondScratchReg, dest.offset), size, extension);
-}
-
-void
-MacroAssemblerMIPS::ma_store(Imm32 imm, const BaseIndex& dest,
-                             LoadStoreSize size, LoadStoreExtension extension)
-{
-    // Make sure that SecondScratchReg contains absolute address so that
-    // offset is 0.
-    asMasm().computeEffectiveAddress(dest, SecondScratchReg);
-
-    // Scrach register is free now, use it for loading imm value
-    ma_li(ScratchRegister, imm);
-
-    // with offset=0 ScratchRegister will not be used in ma_store()
-    // so we can use it as a parameter here
-    ma_store(ScratchRegister, Address(SecondScratchReg, 0), size, extension);
-}
-
 void
 MacroAssemblerMIPSCompat::computeScaledAddress(const BaseIndex& address, Register dest)
 {
@@ -922,49 +552,6 @@ MacroAssemblerMIPS::ma_push(Register r)
 }
 
 // Branches when done from within mips-specific code.
-void
-MacroAssemblerMIPS::ma_b(Register lhs, Register rhs, Label* label, Condition c, JumpKind jumpKind)
-{
-    switch (c) {
-      case Equal :
-      case NotEqual:
-        branchWithCode(getBranchCode(lhs, rhs, c), label, jumpKind);
-        break;
-      case Always:
-        ma_b(label, jumpKind);
-        break;
-      case Zero:
-      case NonZero:
-      case Signed:
-      case NotSigned:
-        MOZ_ASSERT(lhs == rhs);
-        branchWithCode(getBranchCode(lhs, c), label, jumpKind);
-        break;
-      default:
-        Condition cond = ma_cmp(ScratchRegister, lhs, rhs, c);
-        branchWithCode(getBranchCode(ScratchRegister, cond), label, jumpKind);
-        break;
-    }
-}
-
-void
-MacroAssemblerMIPS::ma_b(Register lhs, Imm32 imm, Label* label, Condition c, JumpKind jumpKind)
-{
-    MOZ_ASSERT(c != Overflow);
-    if (imm.value == 0) {
-        if (c == Always || c == AboveOrEqual)
-            ma_b(label, jumpKind);
-        else if (c == Below)
-            ; // This condition is always false. No branch required.
-        else
-            branchWithCode(getBranchCode(lhs, c), label, jumpKind);
-    } else {
-        MOZ_ASSERT(lhs != ScratchRegister);
-        ma_li(ScratchRegister, imm);
-        ma_b(lhs, ScratchRegister, label, c, jumpKind);
-    }
-}
-
 void
 MacroAssemblerMIPS::ma_b(Register lhs, Address addr, Label* label, Condition c, JumpKind jumpKind)
 {
@@ -987,12 +574,6 @@ MacroAssemblerMIPS::ma_b(Address addr, ImmGCPtr imm, Label* label, Condition c,
     ma_b(SecondScratchReg, imm, label, c, jumpKind);
 }
 
-void
-MacroAssemblerMIPS::ma_b(Label* label, JumpKind jumpKind)
-{
-    branchWithCode(getBranchCode(BranchIsJump), label, jumpKind);
-}
-
 void
 MacroAssemblerMIPS::ma_bal(Label* label, DelaySlotFill delaySlotFill)
 {
@@ -1093,276 +674,6 @@ MacroAssemblerMIPS::branchWithCode(InstImm code, Label* label, JumpKind jumpKind
         as_nop();
 }
 
-Assembler::Condition
-MacroAssemblerMIPS::ma_cmp(Register scratch, Register lhs, Register rhs, Condition c)
-{
-    switch (c) {
-      case Above:
-        // bgtu s,t,label =>
-        //   sltu at,t,s
-        //   bne at,$zero,offs
-        as_sltu(scratch, rhs, lhs);
-        return NotEqual;
-      case AboveOrEqual:
-        // bgeu s,t,label =>
-        //   sltu at,s,t
-        //   beq at,$zero,offs
-        as_sltu(scratch, lhs, rhs);
-        return Equal;
-      case Below:
-        // bltu s,t,label =>
-        //   sltu at,s,t
-        //   bne at,$zero,offs
-        as_sltu(scratch, lhs, rhs);
-        return NotEqual;
-      case BelowOrEqual:
-        // bleu s,t,label =>
-        //   sltu at,t,s
-        //   beq at,$zero,offs
-        as_sltu(scratch, rhs, lhs);
-        return Equal;
-      case GreaterThan:
-        // bgt s,t,label =>
-        //   slt at,t,s
-        //   bne at,$zero,offs
-        as_slt(scratch, rhs, lhs);
-        return NotEqual;
-      case GreaterThanOrEqual:
-        // bge s,t,label =>
-        //   slt at,s,t
-        //   beq at,$zero,offs
-        as_slt(scratch, lhs, rhs);
-        return Equal;
-      case LessThan:
-        // blt s,t,label =>
-        //   slt at,s,t
-        //   bne at,$zero,offs
-        as_slt(scratch, lhs, rhs);
-        return NotEqual;
-      case LessThanOrEqual:
-        // ble s,t,label =>
-        //   slt at,t,s
-        //   beq at,$zero,offs
-        as_slt(scratch, rhs, lhs);
-        return Equal;
-      case Equal :
-      case NotEqual:
-      case Zero:
-      case NonZero:
-      case Always:
-      case Signed:
-      case NotSigned:
-        MOZ_CRASH("There is a better way to compare for equality.");
-        break;
-      case Overflow:
-        MOZ_CRASH("Overflow condition not supported for MIPS.");
-        break;
-      default:
-        MOZ_CRASH("Invalid condition for branch.");
-    }
-    return Always;
-}
-
-void
-MacroAssemblerMIPS::ma_cmp_set(Register rd, Register rs, Register rt, Condition c)
-{
-    switch (c) {
-      case Equal :
-        // seq d,s,t =>
-        //   xor d,s,t
-        //   sltiu d,d,1
-        as_xor(rd, rs, rt);
-        as_sltiu(rd, rd, 1);
-        break;
-      case NotEqual:
-        // sne d,s,t =>
-        //   xor d,s,t
-        //   sltu d,$zero,d
-        as_xor(rd, rs, rt);
-        as_sltu(rd, zero, rd);
-        break;
-      case Above:
-        // sgtu d,s,t =>
-        //   sltu d,t,s
-        as_sltu(rd, rt, rs);
-        break;
-      case AboveOrEqual:
-        // sgeu d,s,t =>
-        //   sltu d,s,t
-        //   xori d,d,1
-        as_sltu(rd, rs, rt);
-        as_xori(rd, rd, 1);
-        break;
-      case Below:
-        // sltu d,s,t
-        as_sltu(rd, rs, rt);
-        break;
-      case BelowOrEqual:
-        // sleu d,s,t =>
-        //   sltu d,t,s
-        //   xori d,d,1
-        as_sltu(rd, rt, rs);
-        as_xori(rd, rd, 1);
-        break;
-      case GreaterThan:
-        // sgt d,s,t =>
-        //   slt d,t,s
-        as_slt(rd, rt, rs);
-        break;
-      case GreaterThanOrEqual:
-        // sge d,s,t =>
-        //   slt d,s,t
-        //   xori d,d,1
-        as_slt(rd, rs, rt);
-        as_xori(rd, rd, 1);
-        break;
-      case LessThan:
-        // slt d,s,t
-        as_slt(rd, rs, rt);
-        break;
-      case LessThanOrEqual:
-        // sle d,s,t =>
-        //   slt d,t,s
-        //   xori d,d,1
-        as_slt(rd, rt, rs);
-        as_xori(rd, rd, 1);
-        break;
-      case Zero:
-        MOZ_ASSERT(rs == rt);
-        // seq d,s,$zero =>
-        //   xor d,s,$zero
-        //   sltiu d,d,1
-        as_xor(rd, rs, zero);
-        as_sltiu(rd, rd, 1);
-        break;
-      case NonZero:
-        // sne d,s,$zero =>
-        //   xor d,s,$zero
-        //   sltu d,$zero,d
-        as_xor(rd, rs, zero);
-        as_sltu(rd, zero, rd);
-        break;
-      case Signed:
-        as_slt(rd, rs, zero);
-        break;
-      case NotSigned:
-        // sge d,s,$zero =>
-        //   slt d,s,$zero
-        //   xori d,d,1
-        as_slt(rd, rs, zero);
-        as_xori(rd, rd, 1);
-        break;
-      default:
-        MOZ_CRASH("Invalid condition for ma_cmp_set.");
-    }
-}
-
-void
-MacroAssemblerMIPS::compareFloatingPoint(FloatFormat fmt, FloatRegister lhs, FloatRegister rhs,
-                                         DoubleCondition c, FloatTestKind* testKind,
-                                         FPConditionBit fcc)
-{
-    switch (c) {
-      case DoubleOrdered:
-        as_cun(fmt, lhs, rhs, fcc);
-        *testKind = TestForFalse;
-        break;
-      case DoubleEqual:
-        as_ceq(fmt, lhs, rhs, fcc);
-        *testKind = TestForTrue;
-        break;
-      case DoubleNotEqual:
-        as_cueq(fmt, lhs, rhs, fcc);
-        *testKind = TestForFalse;
-        break;
-      case DoubleGreaterThan:
-        as_colt(fmt, rhs, lhs, fcc);
-        *testKind = TestForTrue;
-        break;
-      case DoubleGreaterThanOrEqual:
-        as_cole(fmt, rhs, lhs, fcc);
-        *testKind = TestForTrue;
-        break;
-      case DoubleLessThan:
-        as_colt(fmt, lhs, rhs, fcc);
-        *testKind = TestForTrue;
-        break;
-      case DoubleLessThanOrEqual:
-        as_cole(fmt, lhs, rhs, fcc);
-        *testKind = TestForTrue;
-        break;
-      case DoubleUnordered:
-        as_cun(fmt, lhs, rhs, fcc);
-        *testKind = TestForTrue;
-        break;
-      case DoubleEqualOrUnordered:
-        as_cueq(fmt, lhs, rhs, fcc);
-        *testKind = TestForTrue;
-        break;
-      case DoubleNotEqualOrUnordered:
-        as_ceq(fmt, lhs, rhs, fcc);
-        *testKind = TestForFalse;
-        break;
-      case DoubleGreaterThanOrUnordered:
-        as_cult(fmt, rhs, lhs, fcc);
-        *testKind = TestForTrue;
-        break;
-      case DoubleGreaterThanOrEqualOrUnordered:
-        as_cule(fmt, rhs, lhs, fcc);
-        *testKind = TestForTrue;
-        break;
-      case DoubleLessThanOrUnordered:
-        as_cult(fmt, lhs, rhs, fcc);
-        *testKind = TestForTrue;
-        break;
-      case DoubleLessThanOrEqualOrUnordered:
-        as_cule(fmt, lhs, rhs, fcc);
-        *testKind = TestForTrue;
-        break;
-      default:
-        MOZ_CRASH("Invalid DoubleCondition.");
-    }
-}
-
-void
-MacroAssemblerMIPS::ma_cmp_set_double(Register dest, FloatRegister lhs, FloatRegister rhs,
-                                      DoubleCondition c)
-{
-    ma_li(dest, Imm32(0));
-    ma_li(ScratchRegister, Imm32(1));
-
-    FloatTestKind moveCondition;
-    compareFloatingPoint(DoubleFloat, lhs, rhs, c, &moveCondition);
-
-    if (moveCondition == TestForTrue)
-        as_movt(dest, ScratchRegister);
-    else
-        as_movf(dest, ScratchRegister);
-}
-
-void
-MacroAssemblerMIPS::ma_cmp_set_float32(Register dest, FloatRegister lhs, FloatRegister rhs,
-                                       DoubleCondition c)
-{
-    ma_li(dest, Imm32(0));
-    ma_li(ScratchRegister, Imm32(1));
-
-    FloatTestKind moveCondition;
-    compareFloatingPoint(SingleFloat, lhs, rhs, c, &moveCondition);
-
-    if (moveCondition == TestForTrue)
-        as_movt(dest, ScratchRegister);
-    else
-        as_movf(dest, ScratchRegister);
-}
-
-void
-MacroAssemblerMIPS::ma_cmp_set(Register rd, Register rs, Imm32 imm, Condition c)
-{
-    ma_li(ScratchRegister, imm);
-    ma_cmp_set(rd, rs, ScratchRegister, c);
-}
-
 void
 MacroAssemblerMIPS::ma_cmp_set(Register rd, Register rs, Address addr, Condition c)
 {
@@ -1378,15 +689,6 @@ MacroAssemblerMIPS::ma_cmp_set(Register dst, Address lhs, Register rhs, Conditio
 }
 
 // fp instructions
-void
-MacroAssemblerMIPS::ma_lis(FloatRegister dest, float value)
-{
-    Imm32 imm(mozilla::BitwiseCast<uint32_t>(value));
-
-    ma_li(ScratchRegister, imm);
-    moveToFloat32(ScratchRegister, dest);
-}
-
 void
 MacroAssemblerMIPS::ma_lid(FloatRegister dest, double value)
 {
@@ -1413,14 +715,6 @@ MacroAssemblerMIPS::ma_lid(FloatRegister dest, double value)
     }
 }
 
-void
-MacroAssemblerMIPS::ma_liNegZero(FloatRegister dest)
-{
-    moveToDoubleLo(zero, dest);
-    ma_li(ScratchRegister, Imm32(INT_MIN));
-    moveToDoubleHi(ScratchRegister, dest);
-}
-
 void
 MacroAssemblerMIPS::ma_mv(FloatRegister src, ValueOperand dest)
 {
@@ -1481,13 +775,6 @@ MacroAssemblerMIPS::ma_sd(FloatRegister ft, Address address)
     }
 }
 
-void
-MacroAssemblerMIPS::ma_sd(FloatRegister ft, BaseIndex address)
-{
-    asMasm().computeScaledAddress(address, SecondScratchReg);
-    ma_sd(ft, Address(SecondScratchReg, address.offset));
-}
-
 void
 MacroAssemblerMIPS::ma_ss(FloatRegister ft, Address address)
 {
@@ -1500,13 +787,6 @@ MacroAssemblerMIPS::ma_ss(FloatRegister ft, Address address)
     }
 }
 
-void
-MacroAssemblerMIPS::ma_ss(FloatRegister ft, BaseIndex address)
-{
-    asMasm().computeScaledAddress(address, SecondScratchReg);
-    ma_ss(ft, Address(SecondScratchReg, address.offset));
-}
-
 void
 MacroAssemblerMIPS::ma_pop(FloatRegister fs)
 {
@@ -1521,24 +801,6 @@ MacroAssemblerMIPS::ma_push(FloatRegister fs)
     ma_sd(fs.doubleOverlay(0), Address(StackPointer, 0));
 }
 
-void
-MacroAssemblerMIPS::ma_bc1s(FloatRegister lhs, FloatRegister rhs, Label* label,
-                            DoubleCondition c, JumpKind jumpKind, FPConditionBit fcc)
-{
-    FloatTestKind testKind;
-    compareFloatingPoint(SingleFloat, lhs, rhs, c, &testKind, fcc);
-    branchWithCode(getBranchCode(testKind, fcc), label, jumpKind);
-}
-
-void
-MacroAssemblerMIPS::ma_bc1d(FloatRegister lhs, FloatRegister rhs, Label* label,
-                            DoubleCondition c, JumpKind jumpKind, FPConditionBit fcc)
-{
-    FloatTestKind testKind;
-    compareFloatingPoint(DoubleFloat, lhs, rhs, c, &testKind, fcc);
-    branchWithCode(getBranchCode(testKind, fcc), label, jumpKind);
-}
-
 bool
 MacroAssemblerMIPSCompat::buildOOLFakeExitFrame(void* fakeReturnAddr)
 {
@@ -2996,22 +2258,6 @@ MacroAssemblerMIPSCompat::storeTypeTag(ImmTag tag, const BaseIndex& dest)
     as_sw(ScratchRegister, SecondScratchReg, TAG_OFFSET);
 }
 
-void
-MacroAssemblerMIPS::ma_call(ImmPtr dest)
-{
-    ma_liPatchable(CallReg, dest);
-    as_jalr(CallReg);
-    as_nop();
-}
-
-void
-MacroAssemblerMIPS::ma_jump(ImmPtr dest)
-{
-    ma_liPatchable(ScratchRegister, dest);
-    as_jr(ScratchRegister);
-    as_nop();
-}
-
 void
 MacroAssemblerMIPSCompat::breakpoint()
 {
@@ -3247,18 +2493,6 @@ MacroAssemblerMIPSCompat::profilerExitFrame()
     branch(GetJitContext()->runtime->jitRuntime()->getProfilerExitFrameTail());
 }
 
-MacroAssembler&
-MacroAssemblerMIPS::asMasm()
-{
-    return *static_cast<MacroAssembler*>(this);
-}
-
-const MacroAssembler&
-MacroAssemblerMIPS::asMasm() const
-{
-    return *static_cast<const MacroAssembler*>(this);
-}
-
 //{{{ check_macroassembler_style
 // ===============================================================
 // Stack manipulation functions.
diff --git a/js/src/jit/mips32/MacroAssembler-mips32.h b/js/src/jit/mips32/MacroAssembler-mips32.h
index 7bc35741bf7..74286995999 100644
--- a/js/src/jit/mips32/MacroAssembler-mips32.h
+++ b/js/src/jit/mips32/MacroAssembler-mips32.h
@@ -12,38 +12,12 @@
 #include "jit/AtomicOp.h"
 #include "jit/IonCaches.h"
 #include "jit/JitFrames.h"
-#include "jit/mips32/Assembler-mips32.h"
+#include "jit/mips-shared/MacroAssembler-mips-shared.h"
 #include "jit/MoveResolver.h"
 
 namespace js {
 namespace jit {
 
-enum LoadStoreSize
-{
-    SizeByte = 8,
-    SizeHalfWord = 16,
-    SizeWord = 32,
-    SizeDouble = 64
-};
-
-enum LoadStoreExtension
-{
-    ZeroExtend = 0,
-    SignExtend = 1
-};
-
-enum JumpKind
-{
-    LongJump = 0,
-    ShortJump = 1
-};
-
-enum DelaySlotFill
-{
-    DontFillDelaySlot = 0,
-    FillDelaySlot = 1
-};
-
 struct ImmTag : public Imm32
 {
     ImmTag(JSValueTag mask)
@@ -61,7 +35,6 @@ struct ImmType : public ImmTag
 static const ValueOperand JSReturnOperand = ValueOperand(JSReturnReg_Type, JSReturnReg_Data);
 static const ValueOperand softfpReturnOperand = ValueOperand(v1, v0);
 
-static Register CallReg = t9;
 static const int defaultShift = 3;
 static_assert(1 << defaultShift == sizeof(JS::Value), "The defaultShift is wrong");
 
@@ -69,107 +42,40 @@ static const uint32_t LOW_32_MASK = (1LL << 32) - 1;
 static const int32_t LOW_32_OFFSET = 0;
 static const int32_t HIGH_32_OFFSET = 4;
 
-class MacroAssemblerMIPS : public Assembler
+class MacroAssemblerMIPS : public MacroAssemblerMIPSShared
 {
-  protected:
-    // Perform a downcast. Should be removed by Bug 996602.
-    MacroAssembler& asMasm();
-    const MacroAssembler& asMasm() const;
-
-    void branchWithCode(InstImm code, Label* label, JumpKind jumpKind);
-    Condition ma_cmp(Register rd, Register lhs, Register rhs, Condition c);
-
-    void compareFloatingPoint(FloatFormat fmt, FloatRegister lhs, FloatRegister rhs,
-                              DoubleCondition c, FloatTestKind* testKind,
-                              FPConditionBit fcc = FCC0);
-
   public:
-    void ma_move(Register rd, Register rs);
-
-    void ma_li(Register dest, ImmGCPtr ptr);
+    using MacroAssemblerMIPSShared::ma_b;
+    using MacroAssemblerMIPSShared::ma_li;
+    using MacroAssemblerMIPSShared::ma_ss;
+    using MacroAssemblerMIPSShared::ma_sd;
+    using MacroAssemblerMIPSShared::ma_load;
+    using MacroAssemblerMIPSShared::ma_store;
+    using MacroAssemblerMIPSShared::ma_cmp_set;
+    using MacroAssemblerMIPSShared::ma_subTestOverflow;
 
     void ma_li(Register dest, AbsoluteLabel* label);
 
-    void ma_li(Register dest, Imm32 imm);
     void ma_liPatchable(Register dest, Imm32 imm);
     void ma_li(Register dest, ImmWord imm);
     void ma_liPatchable(Register dest, ImmPtr imm);
     void ma_liPatchable(Register dest, ImmWord imm);
 
-    // Shift operations
-    void ma_sll(Register rd, Register rt, Imm32 shift);
-    void ma_srl(Register rd, Register rt, Imm32 shift);
-    void ma_sra(Register rd, Register rt, Imm32 shift);
-    void ma_ror(Register rd, Register rt, Imm32 shift);
-    void ma_rol(Register rd, Register rt, Imm32 shift);
-
-    void ma_sll(Register rd, Register rt, Register shift);
-    void ma_srl(Register rd, Register rt, Register shift);
-    void ma_sra(Register rd, Register rt, Register shift);
-    void ma_ror(Register rd, Register rt, Register shift);
-    void ma_rol(Register rd, Register rt, Register shift);
-
-    // Negate
-    void ma_negu(Register rd, Register rs);
-
-    void ma_not(Register rd, Register rs);
-
-    // and
-    void ma_and(Register rd, Register rs);
-    void ma_and(Register rd, Imm32 imm);
-    void ma_and(Register rd, Register rs, Imm32 imm);
-
-    // or
-    void ma_or(Register rd, Register rs);
-    void ma_or(Register rd, Imm32 imm);
-    void ma_or(Register rd, Register rs, Imm32 imm);
-
-    // xor
-    void ma_xor(Register rd, Register rs);
-    void ma_xor(Register rd, Imm32 imm);
-    void ma_xor(Register rd, Register rs, Imm32 imm);
-
     // load
     void ma_load(Register dest, Address address, LoadStoreSize size = SizeWord,
                  LoadStoreExtension extension = SignExtend);
-    void ma_load(Register dest, const BaseIndex& src, LoadStoreSize size = SizeWord,
-                 LoadStoreExtension extension = SignExtend);
 
     // store
     void ma_store(Register data, Address address, LoadStoreSize size = SizeWord,
                   LoadStoreExtension extension = SignExtend);
-    void ma_store(Register data, const BaseIndex& dest, LoadStoreSize size = SizeWord,
-                  LoadStoreExtension extension = SignExtend);
-    void ma_store(Imm32 imm, const BaseIndex& dest, LoadStoreSize size = SizeWord,
-                  LoadStoreExtension extension = SignExtend);
 
     // arithmetic based ops
     // add
-    void ma_addu(Register rd, Register rs, Imm32 imm);
-    void ma_addu(Register rd, Register rs);
-    void ma_addu(Register rd, Imm32 imm);
     void ma_addTestOverflow(Register rd, Register rs, Register rt, Label* overflow);
     void ma_addTestOverflow(Register rd, Register rs, Imm32 imm, Label* overflow);
 
     // subtract
-    void ma_subu(Register rd, Register rs, Imm32 imm);
-    void ma_subu(Register rd, Imm32 imm);
     void ma_subTestOverflow(Register rd, Register rs, Register rt, Label* overflow);
-    void ma_subTestOverflow(Register rd, Register rs, Imm32 imm, Label* overflow);
-
-    // multiplies.  For now, there are only few that we care about.
-    void ma_mult(Register rs, Imm32 imm);
-    void ma_mul_branch_overflow(Register rd, Register rs, Register rt, Label* overflow);
-    void ma_mul_branch_overflow(Register rd, Register rs, Imm32 imm, Label* overflow);
-
-    // divisions
-    void ma_div_branch_overflow(Register rd, Register rs, Register rt, Label* overflow);
-    void ma_div_branch_overflow(Register rd, Register rs, Imm32 imm, Label* overflow);
-
-    // fast mod, uses scratch registers, and thus needs to be in the assembler
-    // implicitly assumes that we can overwrite dest at the beginning of the sequence
-    void ma_mod_mask(Register src, Register dest, Register hold, Register remain,
-                     int32_t shift, Label* negZero = nullptr);
 
     // memory
     // shortcut for when we know we're transferring 32 bits of data
@@ -182,17 +88,8 @@ class MacroAssemblerMIPS : public Assembler
     void ma_pop(Register r);
     void ma_push(Register r);
 
+    void branchWithCode(InstImm code, Label* label, JumpKind jumpKind);
     // branches when done from within mips-specific code
-    void ma_b(Register lhs, Register rhs, Label* l, Condition c, JumpKind jumpKind = LongJump);
-    void ma_b(Register lhs, Imm32 imm, Label* l, Condition c, JumpKind jumpKind = LongJump);
-    void ma_b(Register lhs, ImmPtr imm, Label* l, Condition c, JumpKind jumpKind = LongJump) {
-        ma_b(lhs, ImmWord(uintptr_t(imm.value)), l, c, jumpKind);
-    }
-    void ma_b(Register lhs, ImmGCPtr imm, Label* l, Condition c, JumpKind jumpKind = LongJump) {
-        MOZ_ASSERT(lhs != ScratchRegister);
-        ma_li(ScratchRegister, imm);
-        ma_b(lhs, ScratchRegister, l, c, jumpKind);
-    }
     void ma_b(Register lhs, ImmWord imm, Label* l, Condition c, JumpKind jumpKind = LongJump)
     {
         ma_b(lhs, Imm32(uint32_t(imm.value)), l, c, jumpKind);
@@ -211,13 +108,10 @@ class MacroAssemblerMIPS : public Assembler
         ma_b(ScratchRegister, rhs, l, c, jumpKind);
     }
 
-    void ma_b(Label* l, JumpKind jumpKind = LongJump);
     void ma_bal(Label* l, DelaySlotFill delaySlotFill = FillDelaySlot);
 
     // fp instructions
-    void ma_lis(FloatRegister dest, float value);
     void ma_lid(FloatRegister dest, double value);
-    void ma_liNegZero(FloatRegister dest);
 
     void ma_mv(FloatRegister src, ValueOperand dest);
     void ma_mv(ValueOperand src, FloatRegister dest);
@@ -225,25 +119,11 @@ class MacroAssemblerMIPS : public Assembler
     void ma_ls(FloatRegister fd, Address address);
     void ma_ld(FloatRegister fd, Address address);
     void ma_sd(FloatRegister fd, Address address);
-    void ma_sd(FloatRegister fd, BaseIndex address);
     void ma_ss(FloatRegister fd, Address address);
-    void ma_ss(FloatRegister fd, BaseIndex address);
 
     void ma_pop(FloatRegister fs);
     void ma_push(FloatRegister fs);
 
-    //FP branches
-    void ma_bc1s(FloatRegister lhs, FloatRegister rhs, Label* label, DoubleCondition c,
-                 JumpKind jumpKind = LongJump, FPConditionBit fcc = FCC0);
-    void ma_bc1d(FloatRegister lhs, FloatRegister rhs, Label* label, DoubleCondition c,
-                 JumpKind jumpKind = LongJump, FPConditionBit fcc = FCC0);
-
-    void ma_call(ImmPtr dest);
-
-    void ma_jump(ImmPtr dest);
-
-    void ma_cmp_set(Register dst, Register lhs, Register rhs, Condition c);
-    void ma_cmp_set(Register dst, Register lhs, Imm32 imm, Condition c);
     void ma_cmp_set(Register dst, Register lhs, ImmPtr imm, Condition c) {
         ma_cmp_set(dst, lhs, Imm32(uint32_t(imm.value)), c);
     }
@@ -254,8 +134,6 @@ class MacroAssemblerMIPS : public Assembler
         ma_li(SecondScratchReg, Imm32(uint32_t(imm.value)));
         ma_cmp_set(dst, ScratchRegister, SecondScratchReg, c);
     }
-    void ma_cmp_set_double(Register dst, FloatRegister lhs, FloatRegister rhs, DoubleCondition c);
-    void ma_cmp_set_float32(Register dst, FloatRegister lhs, FloatRegister rhs, DoubleCondition c);
 
     // These fuctions abstract the access to high part of the double precision
     // float register. It is intended to work on both 32 bit and 64 bit
@@ -267,20 +145,6 @@ class MacroAssemblerMIPS : public Assembler
     void moveFromDoubleHi(FloatRegister src, Register dest) {
         as_mfc1(dest, getOddPair(src));
     }
-
-    void moveToDoubleLo(Register src, FloatRegister dest) {
-        as_mtc1(src, dest);
-    }
-    void moveFromDoubleLo(FloatRegister src, Register dest) {
-        as_mfc1(dest, src);
-    }
-
-    void moveToFloat32(Register src, FloatRegister dest) {
-        as_mtc1(src, dest);
-    }
-    void moveFromFloat32(FloatRegister src, Register dest) {
-        as_mfc1(dest, src);
-    }
 };
 
 class MacroAssembler;
diff --git a/js/src/jit/mips32/Trampoline-mips32.cpp b/js/src/jit/mips32/Trampoline-mips32.cpp
index c2bad1f713f..d088e8fa616 100644
--- a/js/src/jit/mips32/Trampoline-mips32.cpp
+++ b/js/src/jit/mips32/Trampoline-mips32.cpp
@@ -13,7 +13,7 @@
 #include "jit/JitFrames.h"
 #include "jit/JitSpewer.h"
 #include "jit/Linker.h"
-#include "jit/mips-shared/Bailouts-mips-shared.h"
+#include "jit/mips32/Bailouts-mips32.h"
 #include "jit/mips32/SharedICHelpers-mips32.h"
 #ifdef JS_ION_PERF
 # include "jit/PerfSpewer.h"
@@ -557,10 +557,8 @@ JitRuntime::generateArgumentsRectifier(JSContext* cx, void** returnAddrOut)
     AutoFlushICache afc("ArgumentsRectifier");
     JitCode* code = linker.newCode<NoGC>(cx, OTHER_CODE);
 
-    CodeOffsetLabel returnLabel(returnOffset);
-    returnLabel.fixup(&masm);
     if (returnAddrOut)
-        *returnAddrOut = (void*) (code->raw() + returnLabel.offset());
+        *returnAddrOut = (void*) (code->raw() + returnOffset);
 
 #ifdef JS_ION_PERF
     writePerfSpewerJitCodeProfile(code, "ArgumentsRectifier");
diff --git a/js/src/jit/mips64/Bailouts-mips64.cpp b/js/src/jit/mips64/Bailouts-mips64.cpp
index 022560a4429..de8b7e2cbbe 100644
--- a/js/src/jit/mips64/Bailouts-mips64.cpp
+++ b/js/src/jit/mips64/Bailouts-mips64.cpp
@@ -4,11 +4,11 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include "jit/mips64/Bailouts-mips64.h"
+
 #include "jscntxt.h"
 #include "jscompartment.h"
 
-#include "jit/mips-shared/Bailouts-mips-shared.h"
-
 using namespace js;
 using namespace js::jit;
 
diff --git a/js/src/jit/mips64/Bailouts-mips64.h b/js/src/jit/mips64/Bailouts-mips64.h
new file mode 100644
index 00000000000..8ddaa02df97
--- /dev/null
+++ b/js/src/jit/mips64/Bailouts-mips64.h
@@ -0,0 +1,77 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef jit_mips64_Bailouts_mips64_h
+#define jit_mips64_Bailouts_mips64_h
+
+#include "jit/Bailouts.h"
+#include "jit/JitCompartment.h"
+
+namespace js {
+namespace jit {
+
+class BailoutStack
+{
+    uintptr_t frameClassId_;
+    // This is pushed in the bailout handler. Both entry points into the
+    // handler inserts their own value int lr, which is then placed onto the
+    // stack along with frameClassId_ above. This should be migrated to ip.
+  public:
+    union {
+        uintptr_t frameSize_;
+        uintptr_t tableOffset_;
+    };
+
+  protected:
+    RegisterDump::FPUArray fpregs_;
+    RegisterDump::GPRArray regs_;
+
+    uintptr_t snapshotOffset_;
+    uintptr_t padding_;
+
+  public:
+    FrameSizeClass frameClass() const {
+        return FrameSizeClass::FromClass(frameClassId_);
+    }
+    uintptr_t tableOffset() const {
+        MOZ_ASSERT(frameClass() != FrameSizeClass::None());
+        return tableOffset_;
+    }
+    uint32_t frameSize() const {
+        if (frameClass() == FrameSizeClass::None())
+            return frameSize_;
+        return frameClass().frameSize();
+    }
+    MachineState machine() {
+        return MachineState::FromBailout(regs_, fpregs_);
+    }
+    SnapshotOffset snapshotOffset() const {
+        MOZ_ASSERT(frameClass() == FrameSizeClass::None());
+        return snapshotOffset_;
+    }
+    uint8_t* parentStackPointer() const {
+        if (frameClass() == FrameSizeClass::None())
+            return (uint8_t*)this + sizeof(BailoutStack);
+        return (uint8_t*)this + offsetof(BailoutStack, snapshotOffset_);
+    }
+    static size_t offsetOfFrameClass() {
+        return offsetof(BailoutStack, frameClassId_);
+    }
+    static size_t offsetOfFrameSize() {
+        return offsetof(BailoutStack, frameSize_);
+    }
+    static size_t offsetOfFpRegs() {
+        return offsetof(BailoutStack, fpregs_);
+    }
+    static size_t offsetOfRegs() {
+        return offsetof(BailoutStack, regs_);
+    }
+};
+
+} // namespace jit
+} // namespace js
+
+#endif /* jit_mips64_Bailouts_mips64_h */
diff --git a/js/src/jit/mips64/Trampoline-mips64.cpp b/js/src/jit/mips64/Trampoline-mips64.cpp
index 80e56e95b10..e6d417f3ecf 100644
--- a/js/src/jit/mips64/Trampoline-mips64.cpp
+++ b/js/src/jit/mips64/Trampoline-mips64.cpp
@@ -13,7 +13,7 @@
 #include "jit/JitFrames.h"
 #include "jit/JitSpewer.h"
 #include "jit/Linker.h"
-#include "jit/mips-shared/Bailouts-mips-shared.h"
+#include "jit/mips64/Bailouts-mips64.h"
 #include "jit/mips64/SharedICHelpers-mips64.h"
 #ifdef JS_ION_PERF
 # include "jit/PerfSpewer.h"
diff --git a/js/src/jit/none/MacroAssembler-none.h b/js/src/jit/none/MacroAssembler-none.h
index e5caac6b754..77ee0255786 100644
--- a/js/src/jit/none/MacroAssembler-none.h
+++ b/js/src/jit/none/MacroAssembler-none.h
@@ -189,7 +189,6 @@ class MacroAssemblerNone : public Assembler
     void nopAlign(size_t) { MOZ_CRASH(); }
     void checkStackAlignment() { MOZ_CRASH(); }
     uint32_t currentOffset() { MOZ_CRASH(); }
-    uint32_t actualOffset(uint32_t) { MOZ_CRASH(); }
     uint32_t labelOffsetToPatchOffset(uint32_t) { MOZ_CRASH(); }
     CodeOffsetLabel labelForPatch() { MOZ_CRASH(); }
 
diff --git a/js/src/jit/shared/Assembler-shared.h b/js/src/jit/shared/Assembler-shared.h
index dadab508249..2703c4ce27f 100644
--- a/js/src/jit/shared/Assembler-shared.h
+++ b/js/src/jit/shared/Assembler-shared.h
@@ -495,8 +495,6 @@ class CodeOffsetLabel
     size_t offset() const {
         return offset_;
     }
-    void fixup(MacroAssembler* masm);
-
 };
 
 // Absolute location of a jump or a label in some generated JitCode block.
diff --git a/js/src/jit/shared/BaselineCompiler-shared.h b/js/src/jit/shared/BaselineCompiler-shared.h
index cc8d63c34ce..bd7af7ac854 100644
--- a/js/src/jit/shared/BaselineCompiler-shared.h
+++ b/js/src/jit/shared/BaselineCompiler-shared.h
@@ -43,13 +43,6 @@ class BaselineCompilerShared
         // If set, insert a PCMappingIndexEntry before encoding the
         // current entry.
         bool addIndexEntry;
-
-        void fixupNativeOffset(MacroAssembler& masm) {
-            CodeOffsetLabel offset(nativeOffset);
-            offset.fixup(&masm);
-            MOZ_ASSERT(offset.offset() <= UINT32_MAX);
-            nativeOffset = (uint32_t) offset.offset();
-        }
     };
 
     js::Vector<PCMappingEntry, 16, SystemAllocPolicy> pcMappingEntries_;
diff --git a/js/src/jit/shared/CodeGenerator-shared.cpp b/js/src/jit/shared/CodeGenerator-shared.cpp
index 447f0fe1a63..7fe2035d5d1 100644
--- a/js/src/jit/shared/CodeGenerator-shared.cpp
+++ b/js/src/jit/shared/CodeGenerator-shared.cpp
@@ -632,10 +632,8 @@ CodeGeneratorShared::encodeSafepoints()
     for (SafepointIndex& index : safepointIndices_) {
         LSafepoint* safepoint = index.safepoint();
 
-        if (!safepoint->encoded()) {
-            safepoint->fixupOffset(&masm);
+        if (!safepoint->encoded())
             safepoints_.encode(safepoint);
-        }
 
         index.resolve();
     }
@@ -710,14 +708,6 @@ CodeGeneratorShared::generateCompactNativeToBytecodeMap(JSContext* cx, JitCode*
     MOZ_ASSERT(nativeToBytecodeTableOffset_ == 0);
     MOZ_ASSERT(nativeToBytecodeNumRegions_ == 0);
 
-    // Iterate through all nativeToBytecode entries, fix up their masm offsets.
-    for (unsigned i = 0; i < nativeToBytecodeList_.length(); i++) {
-        NativeToBytecode& entry = nativeToBytecodeList_[i];
-
-        // Fixup code offsets.
-        entry.nativeOffset = CodeOffsetLabel(masm.actualOffset(entry.nativeOffset.offset()));
-    }
-
     if (!createNativeToBytecodeScriptList(cx))
         return false;
 
@@ -863,12 +853,9 @@ CodeGeneratorShared::generateCompactTrackedOptimizationsMap(JSContext* cx, JitCo
     if (!unique.init())
         return false;
 
-    // Iterate through all entries, fix up their masm offsets and deduplicate
-    // their optimization attempts.
+    // Iterate through all entries to deduplicate their optimization attempts.
     for (size_t i = 0; i < trackedOptimizations_.length(); i++) {
         NativeToTrackedOptimizations& entry = trackedOptimizations_[i];
-        entry.startOffset = CodeOffsetLabel(masm.actualOffset(entry.startOffset.offset()));
-        entry.endOffset = CodeOffsetLabel(masm.actualOffset(entry.endOffset.offset()));
         if (!unique.add(entry.optimizations))
             return false;
     }
diff --git a/js/src/jit/shared/IonAssemblerBuffer.h b/js/src/jit/shared/IonAssemblerBuffer.h
index 8367fa5dbb6..aa4b4dfdddc 100644
--- a/js/src/jit/shared/IonAssemblerBuffer.h
+++ b/js/src/jit/shared/IonAssemblerBuffer.h
@@ -114,7 +114,6 @@ class AssemblerBuffer
     // How many bytes has been committed to the buffer thus far.
     // Does not include tail.
     uint32_t bufferSize;
-    uint32_t lastInstSize;
 
     // Finger for speeding up accesses.
     Slice* finger;
@@ -129,7 +128,6 @@ class AssemblerBuffer
         m_oom(false),
         m_bail(false),
         bufferSize(0),
-        lastInstSize(0),
         finger(nullptr),
         finger_offset(0),
         lifoAlloc_(8192)
@@ -193,6 +191,9 @@ class AssemblerBuffer
     BufferOffset putInt(uint32_t value) {
         return putBytes(sizeof(value), (uint8_t*)&value);
     }
+
+    // Add instSize bytes to this buffer.
+    // The data must fit in a single slice.
     BufferOffset putBytes(uint32_t instSize, uint8_t* inst) {
         if (!ensureSpace(instSize))
             return BufferOffset();
@@ -202,6 +203,25 @@ class AssemblerBuffer
         return ret;
     }
 
+    // Add a potentially large amount of data to this buffer.
+    // The data may be distrubuted across multiple slices.
+    // Return the buffer offset of the first added byte.
+    BufferOffset putBytesLarge(size_t numBytes, const uint8_t* data)
+    {
+        BufferOffset ret = nextOffset();
+        while (numBytes > 0) {
+            if (!ensureSpace(1))
+                return BufferOffset();
+            size_t avail = tail->Capacity() - tail->length();
+            size_t xfer = numBytes < avail ? numBytes : avail;
+            MOZ_ASSERT(xfer > 0, "ensureSpace should have allocated a slice");
+            tail->putBytes(xfer, data);
+            data += xfer;
+            numBytes -= xfer;
+        }
+        return ret;
+    }
+
     unsigned int size() const {
         if (tail)
             return bufferSize + tail->length();
@@ -326,19 +346,6 @@ class AssemblerBuffer
         return BufferOffset(bufferSize);
     }
 
-    // Break the instruction stream so we can go back and edit it at this point
-    void perforate() {
-        Slice* slice = newSlice(lifoAlloc_);
-        if (!slice) {
-            fail_oom();
-            return;
-        }
-
-        bufferSize += tail->length();
-        tail->setNext(slice);
-        tail = slice;
-    }
-
     class AssemblerBufferInstIterator
     {
         BufferOffset bo;
diff --git a/js/src/jit/shared/IonAssemblerBufferWithConstantPools.h b/js/src/jit/shared/IonAssemblerBufferWithConstantPools.h
index eed6ea63291..05f1f1d078b 100644
--- a/js/src/jit/shared/IonAssemblerBufferWithConstantPools.h
+++ b/js/src/jit/shared/IonAssemblerBufferWithConstantPools.h
@@ -9,6 +9,8 @@
 
 #include "mozilla/DebugOnly.h"
 
+#include <algorithm>
+
 #include "jit/JitSpewer.h"
 #include "jit/shared/IonAssemblerBuffer.h"
 
@@ -21,51 +23,14 @@
 // point constants, for loading 32 bit constants on the ARMv6, for absolute
 // branch targets, and in future will be needed for large branches on the ARMv6.
 //
-// The pools are associated with the AssemblerBuffer buffer slices, with at most
-// one pool per slice. When a pool needs to be dumped, the current slice is
-// finished, and this is referred to as a 'perforation' below. The pool data is
-// stored separately from the buffer slice data during assembly and is
-// concatenated together with the instructions when finishing the buffer. The
-// parent AssemblerBuffer slices are extended by the BufferSliceTail class below
-// to include the pool information. The pool guard instructions (the branches
-// around the pools) are included in the buffer slices.
+// For simplicity of the implementation, the constant pools are always placed
+// after the loads referencing them. When a new constant pool load is added to
+// the assembler buffer, a corresponding pool entry is added to the current
+// pending pool. The finishPool() method copies the current pending pool entries
+// into the assembler buffer at the current offset and patches the pending
+// constant pool load instructions.
 //
-// To illustrate.  Without the pools there are just slices of instructions. The
-// slice size may vary - they need not be completely full.
-//
-// -------------     -----------     ------------     -----------
-// | Slice 1   | <-> | Slice 2 | <-> | Slice 3  | <-> | Slice 4 |
-// -------------     -----------     ------------     -----------
-//
-// The pools are only placed at the end of a slice and not all slices will have
-// a pool. There will generally be a guard instruction (G below) jumping around
-// a pool and these guards are included in the slices.
-//
-// --------------     -------------     ---------------     -------------
-// | Slice 1  G | <-> | Slice 2 G | <-> | Slice 3     | <-> | Slice 4 G |
-// --------------     -------------     ---------------     -------------
-//             |                 |                                     |
-//            Pool 1            Pool 2                                Pool 3
-//
-// When finishing the buffer, the slices and pools are concatenated into one
-// code vector, see executableCopy().
-//
-// --------------------------------------------------------------------
-// | Slice 1 G  Pool 1  Slice 2 G  Pool 2  Slice 3  Slice 4 G  Pool 3 |
-// --------------------------------------------------------------------
-//
-// The buffer nextOffset() returns the cumulative size of the buffer slices,
-// that is the instructions including the pool guard instructions, but excluding
-// the content of the pools.
-//
-// The PoolInfo structure stores the final actual position of the end of each
-// pool and these positions are cumulatively built as pools are dumped. It also
-// stores the buffer nextOffset() position at the start of the pool including
-// guards. The difference between these gives the cumulative size of pools
-// dumped which is used to map an index returned by nextOffset() to its final
-// actual position, see poolSizeBefore().
-//
-// Before inserting instructions, or pool entries, it is necessary to determine
+// Before inserting instructions or pool entries, it is necessary to determine
 // if doing so would place a pending pool entry out of reach of an instruction,
 // and if so then the pool must firstly be dumped. With the allocation algorithm
 // used below, the recalculation of all the distances between instructions and
@@ -110,12 +75,10 @@
 namespace js {
 namespace jit {
 
-typedef Vector<BufferOffset, 512, OldJitAllocPolicy> LoadOffsets;
-
 // The allocation unit size for pools.
 typedef int32_t PoolAllocUnit;
 
-struct Pool : public OldJitAllocPolicy
+struct Pool
 {
   private:
     // The maximum program-counter relative offset below which the instruction
@@ -127,14 +90,10 @@ struct Pool : public OldJitAllocPolicy
     // bias of 8.
     const unsigned bias_;
 
-    // The number of PoolAllocUnit sized entires used from the poolData vector.
-    unsigned numEntries_;
-    // The available size of the poolData vector, in PoolAllocUnits.
-    unsigned buffSize;
-    // The content of the pool entries.  Invariant: If poolData_ is nullptr then
-    // buffSize will be zero and oom_ will return true.
-    PoolAllocUnit* poolData_;
-    // Flag that tracks OOM conditions.
+    // The content of the pool entries.
+    Vector<PoolAllocUnit, 8, LifoAllocPolicy<Fallible>> poolData_;
+
+    // Flag that tracks OOM conditions. This is set after any append failed.
     bool oom_;
 
     // The limiting instruction and pool-entry pair. The instruction program
@@ -154,41 +113,31 @@ struct Pool : public OldJitAllocPolicy
     // entries. These instructions need to be patched when the actual position
     // of the instructions and pools are known, and for the code below this
     // occurs when each pool is finished, see finishPool().
-    LoadOffsets loadOffsets;
+    Vector<BufferOffset, 8, LifoAllocPolicy<Fallible>> loadOffsets;
 
+    // Create a Pool. Don't allocate anything from lifoAloc, just capture its reference.
     explicit Pool(size_t maxOffset, unsigned bias, LifoAlloc& lifoAlloc)
       : maxOffset_(maxOffset),
         bias_(bias),
-        numEntries_(0),
-        buffSize(8),
-        poolData_(lifoAlloc.newArrayUninitialized<PoolAllocUnit>(buffSize)),
+        poolData_(lifoAlloc),
         oom_(false),
         limitingUser(),
         limitingUsee(INT_MIN),
-        loadOffsets()
+        loadOffsets(lifoAlloc)
     {
-        if (poolData_ == nullptr) {
-            buffSize = 0;
-            oom_ = true;
-        }
     }
 
-    static const unsigned Garbage = 0xa5a5a5a5;
-    Pool()
-      : maxOffset_(Garbage), bias_(Garbage)
-    { }
-
     // If poolData() returns nullptr then oom_ will also be true.
-    PoolAllocUnit* poolData() const {
-        return poolData_;
+    const PoolAllocUnit* poolData() const {
+        return poolData_.begin();
     }
 
     unsigned numEntries() const {
-        return numEntries_;
+        return poolData_.length();
     }
 
     size_t getPoolSize() const {
-        return numEntries_ * sizeof(PoolAllocUnit);
+        return numEntries() * sizeof(PoolAllocUnit);
     }
 
     bool oom() const {
@@ -205,11 +154,11 @@ struct Pool : public OldJitAllocPolicy
     // does not depend on where the pool is placed.
     void updateLimiter(BufferOffset nextInst) {
         ptrdiff_t oldRange = limitingUsee * sizeof(PoolAllocUnit) - limitingUser.getOffset();
-        ptrdiff_t newRange = numEntries_ * sizeof(PoolAllocUnit) - nextInst.getOffset();
+        ptrdiff_t newRange = getPoolSize() - nextInst.getOffset();
         if (!limitingUser.assigned() || newRange > oldRange) {
             // We have a new largest range!
             limitingUser = nextInst;
-            limitingUsee = numEntries_;
+            limitingUsee = numEntries();
         }
     }
 
@@ -232,93 +181,20 @@ struct Pool : public OldJitAllocPolicy
     unsigned insertEntry(unsigned num, uint8_t* data, BufferOffset off, LifoAlloc& lifoAlloc) {
         if (oom_)
             return OOM_FAIL;
-        if (numEntries_ + num >= buffSize) {
-            // Grow the poolData_ vector.
-            unsigned newSize = buffSize*2;
-            PoolAllocUnit* tmp = lifoAlloc.newArrayUninitialized<PoolAllocUnit>(newSize);
-            if (tmp == nullptr) {
-                oom_ = true;
-                return OOM_FAIL;
-            }
-            mozilla::PodCopy(tmp, poolData_, numEntries_);
-            poolData_ = tmp;
-            buffSize = newSize;
+        unsigned ret = numEntries();
+        if (!poolData_.append((PoolAllocUnit*)data, num) || !loadOffsets.append(off)) {
+            oom_ = true;
+            return OOM_FAIL;
         }
-        mozilla::PodCopy(&poolData_[numEntries_], (PoolAllocUnit*)data, num);
-        loadOffsets.append(off.getOffset());
-        unsigned ret = numEntries_;
-        numEntries_ += num;
         return ret;
     }
 
-    bool reset(LifoAlloc& a) {
-        numEntries_ = 0;
-        buffSize = 8;
-        poolData_ = static_cast<PoolAllocUnit*>(a.alloc(buffSize * sizeof(PoolAllocUnit)));
-        if (poolData_ == nullptr) {
-            oom_ = true;
-            buffSize = 0;
-            return false;
-        }
-
-        new (&loadOffsets) LoadOffsets;
+    void reset() {
+        poolData_.clear();
+        loadOffsets.clear();
 
         limitingUser = BufferOffset();
         limitingUsee = -1;
-        return true;
-    }
-};
-
-
-template <size_t SliceSize, size_t InstSize>
-struct BufferSliceTail : public BufferSlice<SliceSize>
-{
-  private:
-    // Bit vector to record which instructions in the slice have a branch, so
-    // that they can be patched when the final positions are known.
-    mozilla::Array<uint8_t, (SliceSize / InstSize) / 8> isBranch_;
-
-  public:
-    Pool* pool;
-
-    // Flag when the last instruction in the slice is a 'natural' pool guard. A
-    // natural pool guard is a branch in the code that was not explicitly added
-    // to branch around the pool. For now an explict guard branch is always
-    // emitted, so this will always be false.
-    bool isNatural : 1;
-
-  public:
-    explicit BufferSliceTail()
-      : pool(nullptr), isNatural(true)
-    {
-        static_assert(SliceSize % (8 * InstSize) == 0, "SliceSize must be a multple of 8 * InstSize.");
-        mozilla::PodArrayZero(isBranch_);
-    }
-
-  public:
-    bool isBranch(unsigned idx) const {
-        MOZ_ASSERT(idx < this->bytelength_ / InstSize);
-        return (isBranch_[idx >> 3] >> (idx & 0x7)) & 1;
-    }
-
-    bool isNextBranch() const {
-        size_t size = this->bytelength_;
-        MOZ_ASSERT(size < SliceSize);
-        return isBranch(size / InstSize);
-    }
-
-    void markNextAsBranch() {
-        // The caller is expected to ensure that the bytelength_ < SliceSize. See
-        // the assembler's markNextAsBranch() method which firstly creates a new
-        // slice if necessary.
-        MOZ_ASSERT(this->bytelength_ % InstSize == 0);
-        MOZ_ASSERT(this->bytelength_ < SliceSize);
-        size_t idx = this->bytelength_ / InstSize;
-        isBranch_[idx >> 3] |= 1 << (idx & 0x7);
-    }
-
-    BufferSliceTail* getNext() const {
-        return (BufferSliceTail*)this->next_;
     }
 };
 
@@ -354,8 +230,8 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
     };
 
   private:
-    typedef BufferSliceTail<SliceSize, InstSize> BufferSlice;
     typedef AssemblerBuffer<SliceSize, Inst> Parent;
+    using typename Parent::Slice;
 
     // The size of a pool guard, in instructions. A branch around the pool.
     const unsigned guardSize_;
@@ -380,28 +256,24 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
     const size_t instBufferAlign_;
 
     struct PoolInfo {
-        // The number of instructions before the start of the pool. This is a
-        // buffer offset, excluding the pools, but including the guards.
-        size_t offset;
-        // The size of the pool, including padding, but excluding the guard.
-        unsigned size;
-        // The actual offset of the end of the last pool, in bytes from the
-        // beginning of the buffer. The difference between the offset and the
-        // finalPos gives the cumulative number of bytes allocated to pools so
-        // far. This is used when mapping a buffer offset to its actual offset;
-        // the PoolInfo is found using the offset and then the difference can be
-        // applied to convert to the actual offset.
-        size_t finalPos;
-        // Link back to the BufferSlice after which this pool is to be inserted.
-        BufferSlice* slice;
+        // The index of the first entry in this pool.
+        // Pool entries are numbered uniquely across all pools, starting from 0.
+        unsigned firstEntryIndex;
+
+        // The location of this pool's first entry in the main assembler buffer.
+        // Note that the pool guard and header come before this offset which
+        // points directly at the data.
+        BufferOffset offset;
+
+        explicit PoolInfo(unsigned index, BufferOffset data)
+          : firstEntryIndex(index)
+          , offset(data)
+        {
+        }
     };
-    // The number of times we've dumped a pool, and the number of Pool Info
-    // elements used in the poolInfo vector below.
-    unsigned numDumps_;
-    // The number of PoolInfo elements available in the poolInfo vector.
-    size_t poolInfoSize_;
-    // Pointer to a vector of PoolInfo structures. Grown as needed.
-    PoolInfo* poolInfo_;
+
+    // Info for each pool that has already been dumped. This does not include any entries in pool_.
+    Vector<PoolInfo, 8, LifoAllocPolicy<Fallible>> poolInfo_;
 
     // When true dumping pools is inhibited.
     bool canNotPlacePool_;
@@ -435,23 +307,17 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
 
   private:
     // The buffer slices are in a double linked list.
-    BufferSlice* getHead() const {
-        return (BufferSlice*)this->head;
+    Slice* getHead() const {
+        return this->head;
     }
-    BufferSlice* getTail() const {
-        return (BufferSlice*)this->tail;
-    }
-
-    virtual BufferSlice* newSlice(LifoAlloc& a) {
-        BufferSlice* slice = a.new_<BufferSlice>();
-        if (!slice) {
-            this->m_oom = true;
-            return nullptr;
-        }
-        return slice;
+    Slice* getTail() const {
+        return this->tail;
     }
 
   public:
+    // Create an assembler buffer.
+    // Note that this constructor is not allowed to actually allocate memory from this->lifoAlloc_
+    // because the MacroAssembler constructor has not yet created an AutoJitContextAlloc.
     AssemblerBufferWithConstantPools(unsigned guardSize, unsigned headerSize,
                                      size_t instBufferAlign, size_t poolMaxOffset,
                                      unsigned pcBias, uint32_t alignFillInst, uint32_t nopFillInst,
@@ -461,11 +327,9 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
         headerSize_(headerSize),
         poolMaxOffset_(poolMaxOffset),
         pcBias_(pcBias),
-        pool_(),
+        pool_(poolMaxOffset, pcBias, this->lifoAlloc_),
         instBufferAlign_(instBufferAlign),
-        numDumps_(0),
-        poolInfoSize_(8),
-        poolInfo_(nullptr),
+        poolInfo_(this->lifoAlloc_),
         canNotPlacePool_(false),
 #ifdef DEBUG
         canNotPlacePoolStartOffset_(0),
@@ -481,37 +345,16 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
     // We need to wait until an AutoJitContextAlloc is created by the
     // MacroAssembler before allocating any space.
     void initWithAllocator() {
-        poolInfo_ = this->lifoAlloc_.template newArrayUninitialized<PoolInfo>(poolInfoSize_);
-        if (!poolInfo_) {
-            this->fail_oom();
-            return;
-        }
-
-        new (&pool_) Pool (poolMaxOffset_, pcBias_, this->lifoAlloc_);
-        if (pool_.poolData() == nullptr)
-            this->fail_oom();
+        // We hand out references to lifoAlloc_ in the constructor.
+        // Check that no allocations were made then.
+        MOZ_ASSERT(this->lifoAlloc_.isEmpty(), "Illegal LIFO allocations before AutoJitContextAlloc");
     }
 
   private:
-    const PoolInfo& getLastPoolInfo() const {
-        // Return the PoolInfo for the last pool dumped, or a zero PoolInfo
-        // structure if none have been dumped.
-        static const PoolInfo nil = {0, 0, 0, nullptr};
-
-        if (numDumps_ > 0)
-            return poolInfo_[numDumps_ - 1];
-
-        return nil;
-    }
-
     size_t sizeExcludingCurrentPool() const {
         // Return the actual size of the buffer, excluding the current pending
         // pool.
-        size_t codeEnd = this->nextOffset().getOffset();
-        // Convert to an actual final offset, using the cumulative pool size
-        // noted in the PoolInfo.
-        PoolInfo pi = getLastPoolInfo();
-        return codeEnd + (pi.finalPos - pi.offset);
+        return this->nextOffset().getOffset();
     }
 
   public:
@@ -537,21 +380,6 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
         }
     }
 
-    void markNextAsBranch() {
-        // If the previous thing inserted was the last instruction of the node,
-        // then whoops, we want to mark the first instruction of the next node.
-        if (!this->ensureSpace(InstSize))
-            return;
-
-        MOZ_ASSERT(this->getTail() != nullptr);
-        this->getTail()->markNextAsBranch();
-    }
-
-    bool isNextBranch() const {
-        MOZ_ASSERT(this->getTail() != nullptr);
-        return this->getTail()->isNextBranch();
-    }
-
     static const unsigned OOM_FAIL = unsigned(-1);
     static const unsigned NO_DATA = unsigned(-2);
 
@@ -656,8 +484,6 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
         // Now inst is a valid thing to insert into the instruction stream.
         if (pe != nullptr)
             *pe = retPE;
-        if (markAsBranch)
-            markNextAsBranch();
         return this->putBytes(numInst * InstSize, inst);
     }
 
@@ -666,29 +492,9 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
     }
 
   private:
-    PoolInfo getPoolData(BufferSlice* perforatedSlice, size_t perfOffset) const {
-        PoolInfo pi = getLastPoolInfo();
-        size_t prevOffset = pi.offset;
-        size_t prevEnd = pi.finalPos;
-        // Calculate the offset of the start of this pool.
-        size_t initOffset = perfOffset + (prevEnd - prevOffset);
-        size_t finOffset = initOffset;
-        if (pool_.numEntries() != 0) {
-            finOffset += headerSize_ * InstSize;
-            finOffset += pool_.getPoolSize();
-        }
-
-        PoolInfo ret;
-        ret.offset = perfOffset;
-        ret.size = finOffset - initOffset;
-        ret.finalPos = finOffset;
-        ret.slice = perforatedSlice;
-        return ret;
-    }
-
     void finishPool() {
         JitSpew(JitSpew_Pools, "[%d] Attempting to finish pool %d with %d entries.", id,
-                numDumps_, pool_.numEntries());
+                poolInfo_.length(), pool_.numEntries());
 
         if (pool_.numEntries() == 0) {
             // If there is no data in the pool being dumped, don't dump anything.
@@ -700,35 +506,23 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
         MOZ_ASSERT(!canNotPlacePool_);
 
         // Dump the pool with a guard branch around the pool.
-        BufferOffset branch = this->nextOffset();
-        // Mark and emit the guard branch.
-        markNextAsBranch();
-        this->putBytes(guardSize_ * InstSize, nullptr);
+        BufferOffset guard = this->putBytes(guardSize_ * InstSize, nullptr);
+        BufferOffset header = this->putBytes(headerSize_ * InstSize, nullptr);
+        BufferOffset data =
+          this->putBytesLarge(pool_.getPoolSize(), (const uint8_t*)pool_.poolData());
         if (this->oom())
             return;
-        BufferOffset afterPool = this->nextOffset();
-        Asm::WritePoolGuard(branch, this->getInst(branch), afterPool);
 
-        // Perforate the buffer which finishes the current slice and allocates a
-        // new slice. This is necessary because Pools are always placed after
-        // the end of a slice.
-        BufferSlice* perforatedSlice = getTail();
-        BufferOffset perforation = this->nextOffset();
-        Parent::perforate();
-        perforatedSlice->isNatural = false;
-        JitSpew(JitSpew_Pools, "[%d] Adding a perforation at offset %d", id, perforation.getOffset());
+        // We only reserved space for the guard branch and pool header.
+        // Fill them in.
+        BufferOffset afterPool = this->nextOffset();
+        Asm::WritePoolGuard(guard, this->getInst(guard), afterPool);
+        Asm::WritePoolHeader((uint8_t*)this->getInst(header), &pool_, false);
 
         // With the pool's final position determined it is now possible to patch
         // the instructions that reference entries in this pool, and this is
         // done incrementally as each pool is finished.
-        size_t poolOffset = perforation.getOffset();
-        // The cumulative pool size.
-        PoolInfo pi = getLastPoolInfo();
-        size_t magicAlign = pi.finalPos - pi.offset;
-        // Convert poolOffset to it's actual final offset.
-        poolOffset += magicAlign;
-        // Account for the header.
-        poolOffset += headerSize_ * InstSize;
+        size_t poolOffset = data.getOffset();
 
         unsigned idx = 0;
         for (BufferOffset* iter = pool_.loadOffsets.begin();
@@ -736,7 +530,7 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
              ++iter, ++idx)
         {
             // All entries should be before the pool.
-            MOZ_ASSERT(iter->getOffset() < perforation.getOffset());
+            MOZ_ASSERT(iter->getOffset() < guard.getOffset());
 
             // Everything here is known so we can safely do the necessary
             // substitutions.
@@ -747,43 +541,19 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
             // the pool entry that is being loaded.  We need to do a non-trivial
             // amount of math here, since the pool that we've made does not
             // actually reside there in memory.
-            JitSpew(JitSpew_Pools, "[%d] Fixing entry %d offset to %u", id, idx,
-                    codeOffset - magicAlign);
-            Asm::PatchConstantPoolLoad(inst, (uint8_t*)inst + codeOffset - magicAlign);
+            JitSpew(JitSpew_Pools, "[%d] Fixing entry %d offset to %u", id, idx, codeOffset);
+            Asm::PatchConstantPoolLoad(inst, (uint8_t*)inst + codeOffset);
         }
 
         // Record the pool info.
-        if (numDumps_ >= poolInfoSize_) {
-            // Grow the poolInfo vector.
-            poolInfoSize_ *= 2;
-            PoolInfo* tmp = this->lifoAlloc_.template newArrayUninitialized<PoolInfo>(poolInfoSize_);
-            if (tmp == nullptr) {
-                this->fail_oom();
-                return;
-            }
-            mozilla::PodCopy(tmp, poolInfo_, numDumps_);
-            poolInfo_ = tmp;
-        }
-        PoolInfo newPoolInfo = getPoolData(perforatedSlice, perforation.getOffset());
-        MOZ_ASSERT(numDumps_ < poolInfoSize_);
-        poolInfo_[numDumps_] = newPoolInfo;
-        numDumps_++;
-
-        // Bind the current pool to the perforation point, copying the pool
-        // state into the BufferSlice.
-        Pool** tmp = &perforatedSlice->pool;
-        *tmp = static_cast<Pool*>(this->lifoAlloc_.alloc(sizeof(Pool)));
-        if (!*tmp) {
+        unsigned firstEntry = poolEntryCount - pool_.numEntries();
+        if (!poolInfo_.append(PoolInfo(firstEntry, data))) {
             this->fail_oom();
             return;
         }
-        mozilla::PodCopy(*tmp, &pool_, 1);
 
         // Reset everything to the state that it was in when we started.
-        if (!pool_.reset(this->lifoAlloc_)) {
-            this->fail_oom();
-            return;
-        }
+        pool_.reset();
     }
 
   public:
@@ -829,19 +599,6 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
         MOZ_ASSERT(this->nextOffset().getOffset() - canNotPlacePoolStartOffset_ <= canNotPlacePoolMaxInst_ * InstSize);
     }
 
-    size_t poolSizeBefore(size_t offset) const {
-        // Linear search of the poolInfo to find the pool before the given
-        // buffer offset, and then return the cumulative size of the pools
-        // before this offset. This is used to convert a buffer offset to its
-        // final actual offset.
-        unsigned cur = 0;
-        while (cur < numDumps_ && poolInfo_[cur].offset <= offset)
-            cur++;
-        if (cur == 0)
-            return 0;
-        return poolInfo_[cur - 1].finalPos - poolInfo_[cur - 1].offset;
-    }
-
     void align(unsigned alignment) {
         MOZ_ASSERT(IsPowerOfTwo(alignment));
 
@@ -871,89 +628,40 @@ struct AssemblerBufferWithConstantPools : public AssemblerBuffer<SliceSize, Inst
         inhibitNops_ = false;
     }
 
-  private:
-    void patchBranch(Inst* i, unsigned curpool, BufferOffset branch) {
-        const Inst* ci = i;
-        ptrdiff_t offset = Asm::GetBranchOffset(ci);
-        // If the offset is 0, then there is nothing to do.
-        if (offset == 0)
-            return;
-        unsigned destOffset = branch.getOffset() + offset;
-        if (offset > 0) {
-            while (curpool < numDumps_ && poolInfo_[curpool].offset <= (size_t)destOffset) {
-                offset += poolInfo_[curpool].size;
-                curpool++;
-            }
-        } else {
-            // Ignore the pool that comes next, since this is a backwards
-            // branch.
-            for (int p = curpool - 1; p >= 0 && poolInfo_[p].offset > destOffset; p--)
-                offset -= poolInfo_[p].size;
-        }
-        Asm::RetargetNearBranch(i, offset, false);
-    }
-
   public:
-    void executableCopy(uint8_t* dest_) {
+    void executableCopy(uint8_t* dest) {
         if (this->oom())
             return;
         // The pools should have all been flushed, check.
         MOZ_ASSERT(pool_.numEntries() == 0);
-        // Expecting the dest_ to already be aligned to instBufferAlign_, check.
-        MOZ_ASSERT(uintptr_t(dest_) == ((uintptr_t(dest_) + instBufferAlign_ - 1) & ~(instBufferAlign_ - 1)));
-        // Assuming the Instruction size is 4 bytes, check.
-        static_assert(InstSize == sizeof(uint32_t), "Assuming instruction size is 4 bytes");
-        uint32_t* dest = (uint32_t*)dest_;
-        unsigned curIndex = 0;
-        size_t curInstOffset = 0;
-        for (BufferSlice* cur = getHead(); cur != nullptr; cur = cur->getNext()) {
-            uint32_t* src = (uint32_t*)&cur->instructions;
-            unsigned numInsts = cur->length() / InstSize;
-            for (unsigned idx = 0; idx < numInsts; idx++, curInstOffset += InstSize) {
-                // Is the current instruction a branch?
-                if (cur->isBranch(idx)) {
-                    // It's a branch, fix up the branchiness!
-                    patchBranch((Inst*)&src[idx], curIndex, BufferOffset(curInstOffset));
-                }
-                dest[idx] = src[idx];
-            }
-            dest += numInsts;
-            Pool* curPool = cur->pool;
-            if (curPool != nullptr) {
-                if (curPool->oom()) {
-                    this->fail_oom();
-                    return;
-                }
-
-                // Have the repatcher move on to the next pool.
-                curIndex++;
-                // Copying the pool into place.
-                uint8_t* poolDest = (uint8_t*)dest;
-                Asm::WritePoolHeader(poolDest, curPool, cur->isNatural);
-                poolDest += headerSize_ * InstSize;
-
-                memcpy(poolDest, curPool->poolData(), curPool->getPoolSize());
-                poolDest += curPool->getPoolSize();
-
-                dest = (uint32_t*)poolDest;
-            }
+        for (Slice* cur = getHead(); cur != nullptr; cur = cur->getNext()) {
+            memcpy(dest, &cur->instructions[0], cur->length());
+            dest += cur->length();
         }
     }
 
   public:
     size_t poolEntryOffset(PoolEntry pe) const {
-        // Linear search of all the pools to locate the given PoolEntry's
-        // PoolInfo and to return the actual offset of the pool entry in the
-        // finished code object.
-        size_t offset = pe.index() * sizeof(PoolAllocUnit);
-        for (unsigned poolNum = 0; poolNum < numDumps_; poolNum++) {
-            PoolInfo* pi = &poolInfo_[poolNum];
-            unsigned size = pi->slice->pool->getPoolSize();
-            if (size > offset)
-                return pi->finalPos - pi->size + headerSize_ * InstSize + offset;
-            offset -= size;
-        }
-        MOZ_CRASH("Entry is not in a pool");
+        MOZ_ASSERT(pe.index() < poolEntryCount - pool_.numEntries(),
+                   "Invalid pool entry, or not flushed yet.");
+        // Find the pool containing pe.index().
+        // The array is sorted, so we can use a binary search.
+        auto b = poolInfo_.begin(), e = poolInfo_.end();
+        // A note on asymmetric types in the upper_bound comparator:
+        // http://permalink.gmane.org/gmane.comp.compilers.clang.devel/10101
+        auto i = std::upper_bound(b, e, pe.index(), [](size_t value, const PoolInfo& entry) {
+            return value < entry.firstEntryIndex;
+        });
+        // Since upper_bound finds the first pool greater than pe,
+        // we want the previous one which is the last one less than or equal.
+        MOZ_ASSERT(i != b, "PoolInfo not sorted or empty?");
+        --i;
+        // The i iterator now points to the pool containing pe.index.
+        MOZ_ASSERT(i->firstEntryIndex <= pe.index() &&
+                   (i + 1 == e || (i + 1)->firstEntryIndex > pe.index()));
+        // Compute the byte offset into the pool.
+        unsigned relativeIndex = pe.index() - i->firstEntryIndex;
+        return i->offset.getOffset() + relativeIndex * sizeof(PoolAllocUnit);
     }
 };
 
diff --git a/js/src/jit/x64/Trampoline-x64.cpp b/js/src/jit/x64/Trampoline-x64.cpp
index 66bd0c8aeff..9d04f663a0f 100644
--- a/js/src/jit/x64/Trampoline-x64.cpp
+++ b/js/src/jit/x64/Trampoline-x64.cpp
@@ -543,10 +543,8 @@ JitRuntime::generateArgumentsRectifier(JSContext* cx, void** returnAddrOut)
     writePerfSpewerJitCodeProfile(code, "ArgumentsRectifier");
 #endif
 
-    CodeOffsetLabel returnLabel(returnOffset);
-    returnLabel.fixup(&masm);
     if (returnAddrOut)
-        *returnAddrOut = (void*) (code->raw() + returnLabel.offset());
+        *returnAddrOut = (void*)(code->raw() + returnOffset);
     return code;
 }
 
diff --git a/js/src/jit/x86-shared/Assembler-x86-shared.h b/js/src/jit/x86-shared/Assembler-x86-shared.h
index 927ab518263..057aab2a860 100644
--- a/js/src/jit/x86-shared/Assembler-x86-shared.h
+++ b/js/src/jit/x86-shared/Assembler-x86-shared.h
@@ -3123,10 +3123,6 @@ class AssemblerX86Shared : public AssemblerShared
     }
 
     // Defined for compatibility with ARM's assembler
-    uint32_t actualOffset(uint32_t x) {
-        return x;
-    }
-
     uint32_t actualIndex(uint32_t x) {
         return x;
     }
diff --git a/js/src/jit/x86/Trampoline-x86.cpp b/js/src/jit/x86/Trampoline-x86.cpp
index ad97991717f..e74043c513b 100644
--- a/js/src/jit/x86/Trampoline-x86.cpp
+++ b/js/src/jit/x86/Trampoline-x86.cpp
@@ -539,10 +539,8 @@ JitRuntime::generateArgumentsRectifier(JSContext* cx, void** returnAddrOut)
     writePerfSpewerJitCodeProfile(code, "ArgumentsRectifier");
 #endif
 
-    CodeOffsetLabel returnLabel(returnOffset);
-    returnLabel.fixup(&masm);
     if (returnAddrOut)
-        *returnAddrOut = (void*) (code->raw() + returnLabel.offset());
+        *returnAddrOut = (void*) (code->raw() + returnOffset);
     return code;
 }
 
diff --git a/js/src/js.msg b/js/src/js.msg
index b404b57aede..cffa1e7c06e 100644
--- a/js/src/js.msg
+++ b/js/src/js.msg
@@ -244,7 +244,6 @@ MSG_DEF(JSMSG_DECLARATION_AFTER_EXPORT,0, JSEXN_SYNTAXERR, "missing declaration
 MSG_DEF(JSMSG_DECLARATION_AFTER_IMPORT,0, JSEXN_SYNTAXERR, "missing declaration after 'import' keyword")
 MSG_DEF(JSMSG_DEPRECATED_DELETE_OPERAND, 0, JSEXN_SYNTAXERR, "applying the 'delete' operator to an unqualified name is deprecated")
 MSG_DEF(JSMSG_DEPRECATED_FLAGS_ARG,    0, JSEXN_NONE, "flags argument of String.prototype.{search,match,replace} is deprecated")
-MSG_DEF(JSMSG_DEPRECATED_LET_BLOCK,      0, JSEXN_NONE, "JavaScript 1.7's let blocks are deprecated")
 MSG_DEF(JSMSG_DEPRECATED_FOR_EACH,     0, JSEXN_NONE, "JavaScript 1.6's for-each-in loops are deprecated; consider using ES6 for-of instead")
 MSG_DEF(JSMSG_DEPRECATED_OCTAL,        0, JSEXN_SYNTAXERR, "octal literals and octal escape sequences are deprecated")
 MSG_DEF(JSMSG_DEPRECATED_PRAGMA,       1, JSEXN_NONE, "Using //@ to indicate {0} pragmas is deprecated. Use //# instead")
diff --git a/js/src/jsapi-tests/testEnclosingFunction.cpp b/js/src/jsapi-tests/testEnclosingFunction.cpp
index c59e5727f79..4482d4e589f 100644
--- a/js/src/jsapi-tests/testEnclosingFunction.cpp
+++ b/js/src/jsapi-tests/testEnclosingFunction.cpp
@@ -55,7 +55,7 @@ BEGIN_TEST(test_enclosingFunction)
     EXEC("s2()()");
     CHECK(foundFun == fun);
 
-    const char s3chars[] = "return function() { let (x) { function g() { checkEnclosing() } return g() } }";
+    const char s3chars[] = "return function() { { let x; function g() { checkEnclosing() } return g() } }";
     CHECK(JS::CompileFunction(cx, emptyScopeChain, options, "s3", 0, nullptr, s3chars,
                               strlen(s3chars), &fun));
     CHECK(fun);
diff --git a/js/src/moz.build b/js/src/moz.build
index 8b09b5a00c6..1f62b5fe464 100644
--- a/js/src/moz.build
+++ b/js/src/moz.build
@@ -487,6 +487,7 @@ elif CONFIG['JS_CODEGEN_MIPS32'] or CONFIG['JS_CODEGEN_MIPS64']:
         'jit/mips-shared/BaselineIC-mips-shared.cpp',
         'jit/mips-shared/CodeGenerator-mips-shared.cpp',
         'jit/mips-shared/Lowering-mips-shared.cpp',
+        'jit/mips-shared/MacroAssembler-mips-shared.cpp',
         'jit/mips-shared/MoveEmitter-mips-shared.cpp',
     ]
     if CONFIG['JS_CODEGEN_MIPS32']:
diff --git a/js/src/tests/js1_7/block/browser.js b/js/src/tests/js1_7/block/browser.js
deleted file mode 100644
index e69de29bb2d..00000000000
diff --git a/js/src/tests/js1_7/block/order-of-operation.js b/js/src/tests/js1_7/block/order-of-operation.js
deleted file mode 100644
index 3ea224669b4..00000000000
--- a/js/src/tests/js1_7/block/order-of-operation.js
+++ /dev/null
@@ -1,153 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER     = "(none)";
-var summary = "Test let and order of operation issues";
-var actual, expect;
-
-printBugNumber(BUGNUMBER);
-printStatus(summary);
-
-/**************
- * BEGIN TEST *
- **************/
-
-var failed = false;
-
-function f1(x)
-{
-  let (foo) {
-    // scope of lhs x includes rhs, so x is NaN here -- bug 344952
-    let x = ++x;
-    return x;
-  }
-}
-
-function f2(x)
-{
-  let (foo)
-  {
-    // scope of lhs x includes rhs, so x is NaN here -- bug 344952
-    let x = x++;
-    return x;
-  }
-}
-
-function f3(x)
-{
-  let (foo)
-  {
-    var q = x;
-    let (x = x++)
-    {
-      if (x != q)
-        throw "f3():\n" +
-          "  expected: x == q\n" +
-          "  actual:   x != q " +
-          "(where x == " + x + ", q == " + q + ")\n";
-    }
-    return x;
-  }
-}
-
-function f4(x)
-{
-  var y = 7;
-  let (y = x, x = 3)
-  {
-    var q = 7 + x;
-  }
-  return x + y + q;
-}
-
-function f5(x)
-{
-  var q = x++;
-  let (y = x, r = 17, m = 32) {
-    return function(code)
-    {
-      return eval(code);
-    };
-  }
-}
-
-function f6() {
-  let (foo)
-  {
-    var i=3;
-    for (let i=i;;) { if (i != 3) throw "f6(): fail 1"; i = 7; break; }
-    if (i != 3) throw "f6(): fail 2";
-  }
-}
-
-try
-{
-/*
-  var rv = f1(5);
-  if (!isNaN(rv))
-    throw "f1(5):\n" +
-      "  expected:  NaN\n" +
-      "  actual:    " + rv;
-
-  rv = f2(5);
-  if (!isNaN(rv))
-    throw "f2(5):\n" +
-      "  expected:  NaN\n" +
-      "  actual:    " + rv;
-
-  rv = f3(8);
-  if (rv != 9)
-  throw "f3(8):\n" +
-  "  expected:  9\n" +
-  "  actual:    " + rv;
-*/
-
-  rv = f4(13);
-  if (rv != 30)
-    throw "f4(13):\n" +
-      "  expected:  30\n" +
-      "  actual:    " + rv;
-
-  var fun = f5(2);
-
-  rv = fun("q");
-  if (rv != 2)
-    throw "fun('q'):\n" +
-      "  expected:  2\n" +
-      "  actual:    " + rv;
-
-  rv = fun("x");
-  if (rv != 3)
-    throw "fun('x'):\n" +
-      "  expected:  3\n" +
-      "  actual:    " + rv;
-
-  rv = fun("y");
-  if (rv != 3)
-    throw "fun('y'):\n" +
-      "  expected:  3\n" +
-      "  actual:    " + rv;
-
-  rv = fun("let (y = y) { y += 32; }; y");
-  if (rv != 3)
-    throw "fun('let (y = y) { y += 32; }; y'):\n" +
-      "  expected:  3\n" +
-      "  actual:    " + rv;
-
-/*
-  f6();
-*/
-}
-catch (e)
-{
-  print(e.toSource());
-  failed = e;
-}
-
-expect = false;
-actual = failed;
-
-reportCompare(expect, actual, summary);
diff --git a/js/src/tests/js1_7/block/regress-341939.js b/js/src/tests/js1_7/block/regress-341939.js
deleted file mode 100644
index f7043dd1b75..00000000000
--- a/js/src/tests/js1_7/block/regress-341939.js
+++ /dev/null
@@ -1,25 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 341939;
-var summary = 'Let block does not require semicolon';
-var actual = '';
-var expect = 'No Error';
-
-printBugNumber(BUGNUMBER);
-printStatus (summary);
-
-try
-{ 
-  eval('let (a) {} print(42);');
-  actual = 'No Error';
-}
-catch(ex)
-{
-  actual = ex + '';
-}
-
-reportCompare(expect, actual, summary);
diff --git a/js/src/tests/js1_7/block/regress-343765.js b/js/src/tests/js1_7/block/regress-343765.js
deleted file mode 100644
index e0a41fbc2e3..00000000000
--- a/js/src/tests/js1_7/block/regress-343765.js
+++ /dev/null
@@ -1,95 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 343765;
-var summary = 'Function defined in a let statement/expression does not work correctly outside the let scope';
-var actual = '';
-var expect = '';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
- 
-  print("SECTION 1");
-  try {
-    let (a = 2, b = 3) { function f() { return String([a,b]); } f(); throw 42; }
-  } catch (e) {
-    f();
-  }
-
-  reportCompare(expect, actual, summary);
-
-  print("SECTION 2");
-  try {
-    with ({a:2,b:3}) { function f() { return String([a,b]); } f(); throw 42; }
-  } catch (e) {
-    f();
-  }
-
-  print("SECTION 3");
-  function g3() {
-    print("Here!");
-    with ({a:2,b:3}) {
-      function f() {
-        return String([a,b]);
-      }
-
-      f();
-      return f;
-    }
-  }
-
-  k = g3();
-  k();
-
-  print("SECTION 4");
-  function g4() {
-    print("Here!");
-    let (a=2,b=3) {
-      function f() {
-        return String([a,b]);
-      }
-
-      f();
-      return f;
-    }
-  }
-
-  k = g4();
-  k();
-
-  print("SECTION 5");
-  function g5() {
-    print("Here!");
-    let (a=2,b=3) {
-      function f() {
-        return String([a,b]);
-      }
-
-      f();
-      yield f;
-    }
-  }
-
-  k = g5().next();
-  k();
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
-
-function returnResult(a)
-{
-  return a + '';
-}
diff --git a/js/src/tests/js1_7/block/regress-344139.js b/js/src/tests/js1_7/block/regress-344139.js
deleted file mode 100644
index 3293cc2f329..00000000000
--- a/js/src/tests/js1_7/block/regress-344139.js
+++ /dev/null
@@ -1,92 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER     = "344139";
-var summary = "Basic let functionality";
-var actual, expect;
-
-printBugNumber(BUGNUMBER);
-printStatus(summary);
-
-/**************
- * BEGIN TEST *
- **************/
-
-var failed = false;
-
-var x = 7;
-
-function f1()
-{
-  let x = 5;
-  return x;
-}
-
-function f2()
-{
-  let x = 5;
-  x = 3;
-  return x;
-}
-
-function f3()
-{
-  let x = 5;
-  x += x;
-  return x;
-}
-
-function f4()
-{
-  var v = 5;
-  let q = 17;
-
-  // 0+1+2+...+8+9 == 45
-  for (let v = 0; v < 10; v++)
-    q += v;
-
-  if (q != 62)
-    throw "f4(): wrong value for q\n" +
-      "  expected: 62\n" +
-      "  actual:   " + q;
-
-  return v;
-}
-
-try
-{
-  if (f1() != 5 || x != 7)
-    throw "f1() == 5";
-  if (f2() != 3 || x != 7)
-    throw "f2() == 3";
-  if (f3() != 10 || x != 7)
-    throw "f3() == 10";
-
-  if (f4() != 5)
-    throw "f4() == 5";
-
-  var bad = true;
-  try
-  {
-    eval("q++"); // force error at runtime
-  }
-  catch (e)
-  {
-    if (e instanceof ReferenceError)
-      bad = false;
-  }
-  if (bad)
-    throw "f4(): q escaping scope!";
-}
-catch (e)
-{
-  failed = e;
-}
-
-expect = false;
-actual = failed;
-
-reportCompare(expect, actual, summary);
diff --git a/js/src/tests/js1_7/block/regress-344370.js b/js/src/tests/js1_7/block/regress-344370.js
deleted file mode 100644
index 119c3d169bc..00000000000
--- a/js/src/tests/js1_7/block/regress-344370.js
+++ /dev/null
@@ -1,28 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 344370;
-var summary = 'let declaration in let statement shows assertion';
-var actual = 'No Crash';
-var expect = 'No Crash';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
- 
-  let (a = 2) { let b = 3; [a, b]; }
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-348685.js b/js/src/tests/js1_7/block/regress-348685.js
deleted file mode 100644
index 5e5ab21ca7f..00000000000
--- a/js/src/tests/js1_7/block/regress-348685.js
+++ /dev/null
@@ -1,47 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 348685;
-var summary = 'Let scoped variables should not be referenced outside blocks';
-var actual = '';
-var expect = '';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
- 
-  function f() {
-    for (let i = 0; i < 2; i++) {
-      let j = 42;
-      function g() {}
-    }
-    var a = i;
-    print(a);
-    print(i);
-    return i;
-  }
-
-  expect = /ReferenceError: (i|"i") is not defined/;
-
-  try
-  {
-    f();
-  }
-  catch(ex)
-  {
-    actual = ex + '';
-  }
-  reportMatch(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-349283.js b/js/src/tests/js1_7/block/regress-349283.js
deleted file mode 100644
index 1a4f95d9147..00000000000
--- a/js/src/tests/js1_7/block/regress-349283.js
+++ /dev/null
@@ -1,30 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 349283;
-var summary = 'Do not crash with let statement in with block';
-var actual = 'No Crash';
-var expect = 'No Crash';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
- 
-  with({b:2}) {
-    let c = 3;
-  }
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-349298.js b/js/src/tests/js1_7/block/regress-349298.js
deleted file mode 100644
index a6106964f12..00000000000
--- a/js/src/tests/js1_7/block/regress-349298.js
+++ /dev/null
@@ -1,38 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 349298;
-var summary = 'Do not bogo assert';
-var actual = 'No Crash';
-var expect = 'No Crash';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  try
-  {
-    eval('(function() { for(i=0;i<4;++i) let x = 4; })');
-  }
-  catch(ex)
-  {
-    // See https://bugzilla.mozilla.org/show_bug.cgi?id=408957
-    summary = 'let declaration must be direct child of block or top-level implicit block';
-    expect = 'SyntaxError';
-    actual = ex.name;
-  }
- 
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-349507.js b/js/src/tests/js1_7/block/regress-349507.js
deleted file mode 100644
index e0c4dc4daf9..00000000000
--- a/js/src/tests/js1_7/block/regress-349507.js
+++ /dev/null
@@ -1,35 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 349507;
-var summary = 'Do not assert with let block, let statement and const';
-var actual = '';
-var expect = '';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  try
-  {
-    eval('(function() { let(x = 1) { const b = 2 }; let b = 3; })');
-  }
-  catch(ex)
-  {
-    actual = ex + '';
-  }
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-349962.js b/js/src/tests/js1_7/block/regress-349962.js
deleted file mode 100644
index c838975ab5c..00000000000
--- a/js/src/tests/js1_7/block/regress-349962.js
+++ /dev/null
@@ -1,27 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 349962;
-var summary = 'let variable bound to nested function expressions'
-  var actual = 'No Crash';
-var expect = 'No Crash';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
- 
-  (function() { let z = (function () { function a() { } })(); })()
-    reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-350279.js b/js/src/tests/js1_7/block/regress-350279.js
deleted file mode 100644
index 4623c439bb3..00000000000
--- a/js/src/tests/js1_7/block/regress-350279.js
+++ /dev/null
@@ -1,36 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 350279;
-var summary = 'Do not assert: left->pn_type == TOK_RC';
-var actual = 'No Crash';
-var expect = 'No Crash';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  expect = /SyntaxError: /;
-  try
-  {
-    eval('let [2 for (x in [])] = 4;');
-  }
-  catch(ex)
-  {
-    actual = ex + '';
-  }
-
-  reportMatch(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-350730.js b/js/src/tests/js1_7/block/regress-350730.js
deleted file mode 100644
index 0bbf56b9431..00000000000
--- a/js/src/tests/js1_7/block/regress-350730.js
+++ /dev/null
@@ -1,38 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 350730;
-var summary = 'Do not assert: pn2->pn_slot >= 0 || varOrConst [@ EmitVariables]';
-var actual = 'No Crash';
-var expect = 'No Crash';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  try
-  {
-    eval('with({}) let y;');
-  }
-  catch(ex)
-  {
-    // See https://bugzilla.mozilla.org/show_bug.cgi?id=408957
-    summary = 'let declaration must be direct child of block or top-level implicit block';
-    expect = 'SyntaxError';
-    actual = ex.name;
-  }
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-350793-01.js b/js/src/tests/js1_7/block/regress-350793-01.js
deleted file mode 100644
index b05e2f03ee0..00000000000
--- a/js/src/tests/js1_7/block/regress-350793-01.js
+++ /dev/null
@@ -1,39 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 350793;
-var summary = 'for-in loops must be yieldable';
-var actual = 'No Crash';
-var expect = 'No Crash';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  function foo()
-  {
-    function gen() { for(let itty in [5,6,7,8]) yield ({ }); }
-
-    iter = gen();
-
-    let count = 0;
-    for each(let _ in iter)
-      ++count;
-  }
-
-  foo();
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-351606.js b/js/src/tests/js1_7/block/regress-351606.js
deleted file mode 100644
index b5cb5935244..00000000000
--- a/js/src/tests/js1_7/block/regress-351606.js
+++ /dev/null
@@ -1,20 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 351606;
-var summary = 'Do not assert with nested for..in and throw';
-var actual = 'No Crash';
-var expect = 'No Crash';
-
-enterFunc ('test');
-printBugNumber(BUGNUMBER);
-printStatus (summary);
-
-(function () {for (let d in [1,2,3,4]) try { for (let a in [5,6,7,8]) (( function() { throw 9; } )()); } catch(c) {  }});
-
-reportCompare(expect, actual, summary);
-
-
diff --git a/js/src/tests/js1_7/block/regress-352092.js b/js/src/tests/js1_7/block/regress-352092.js
deleted file mode 100644
index d80fa3ad7df..00000000000
--- a/js/src/tests/js1_7/block/regress-352092.js
+++ /dev/null
@@ -1,38 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 352092;
-var summary = 'Do not assert on with() let';
-var actual = 'No Crash';
-var expect = 'No Crash';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  try
-  { 
-    eval('let(z) { with({}) let y = 3; }');
-  }
-  catch(ex)
-  {
-    // See https://bugzilla.mozilla.org/show_bug.cgi?id=408957
-    summary = 'let declaration must be direct child of block or top-level implicit block';
-    expect = 'SyntaxError';
-    actual = ex.name;
-  }
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-352267.js b/js/src/tests/js1_7/block/regress-352267.js
deleted file mode 100644
index 6a7819877ea..00000000000
--- a/js/src/tests/js1_7/block/regress-352267.js
+++ /dev/null
@@ -1,28 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 352267;
-var summary = 'Do not assert with |if|, block, |let|';
-var actual = 'No Crash';
-var expect = 'No Crash';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
- 
-  uneval(function() { if (y) { { let set = 4.; } } else if ([1,2,3]) { } });
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-352422.js b/js/src/tests/js1_7/block/regress-352422.js
deleted file mode 100644
index e3bec60629c..00000000000
--- a/js/src/tests/js1_7/block/regress-352422.js
+++ /dev/null
@@ -1,37 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 352422;
-var summary = 'let declaration must be direct child of block, ' + 
-  'top-level implicit block, or switch body block';
-var actual = '';
-var expect = 'SyntaxError';
-
-// See https://bugzilla.mozilla.org/show_bug.cgi?id=408957
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  try
-  {
-    eval('(function() { with({}) let x; })');
-  }
-  catch(ex)
-  {
-    actual = ex.name;
-  }
- 
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-352609.js b/js/src/tests/js1_7/block/regress-352609.js
deleted file mode 100644
index 0722d0bcfdb..00000000000
--- a/js/src/tests/js1_7/block/regress-352609.js
+++ /dev/null
@@ -1,36 +0,0 @@
-// |reftest| skip -- obsolete test
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 352609;
-var summary = 'decompilation of |let| expression for |is not a function| error';
-var actual = '';
-var expect = '';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  expect = /TypeError: (p.z = \(let \(x\) x\)|.*Undefined.*) is not a function/;
-  try
-  {
-    var p = {}; (p.z = let(x) x)()
-  }
-  catch(ex)
-  {
-    actual = ex + '';
-  }
-  reportMatch(expect, actual, 'p = {}; (p.z = let(x) x)()');
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-352624.js b/js/src/tests/js1_7/block/regress-352624.js
deleted file mode 100644
index 73846637f6f..00000000000
--- a/js/src/tests/js1_7/block/regress-352624.js
+++ /dev/null
@@ -1,35 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 352624;
-var summary = 'Do not crash with |let (map)| in WAY_TOO_MUCH_GC builds';
-var actual = 'No Crash';
-var expect = 'No Crash';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-  printStatus('This bug can only be verified with a WAY_TOO_MUCH_GC build');
-
-  let (x = [].map(function () {})) { x; }
-  reportCompare(expect, actual, summary + ': 1');
-
-  var g = function() {};
-  (function() { let x = [].map(function () {}); g(x); })()
-    reportCompare(expect, actual, summary + ': 3');
-
-  for(let x in [1].map(function () { })) { }
-  reportCompare(expect, actual, summary + ': 4');
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-352786.js b/js/src/tests/js1_7/block/regress-352786.js
deleted file mode 100644
index 5b0606af11d..00000000000
--- a/js/src/tests/js1_7/block/regress-352786.js
+++ /dev/null
@@ -1,37 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 352786;
-var summary = 'let declaration must be direct child of block, ' + 
-  'top-level implicit block, or switch body block';
-var actual = '';
-var expect = 'SyntaxError';
-
-// See https://bugzilla.mozilla.org/show_bug.cgi?id=408957
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  try
-  {
-    eval('(function() { { if(0) let x; } })');
-  }
-  catch(ex)
-  {
-    actual = ex.name;
-  }
- 
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-352907.js b/js/src/tests/js1_7/block/regress-352907.js
deleted file mode 100644
index 410fabcba21..00000000000
--- a/js/src/tests/js1_7/block/regress-352907.js
+++ /dev/null
@@ -1,37 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 352907;
-var summary = 'let declaration must be direct child of block, ' + 
-  'top-level implicit block, or switch body block';
-var actual = '';
-var expect = 'SyntaxError';
-
-// See https://bugzilla.mozilla.org/show_bug.cgi?id=408957
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  try
-  {
-    eval('(function() { while(0) while(0) let k=3; return k; })');
-  }
-  catch(ex)
-  {
-    actual = ex.name;
-  }
- 
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-357754.js b/js/src/tests/js1_7/block/regress-357754.js
deleted file mode 100644
index 83a247b9d98..00000000000
--- a/js/src/tests/js1_7/block/regress-357754.js
+++ /dev/null
@@ -1,65 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/*
- * Any copyright is dedicated to the Public Domain.
- * http://creativecommons.org/licenses/publicdomain/
- * Contributor: Blake Kaplan
- */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 357754;
-var summary = 'top level closures with let-bound varibles';
-var actual = '';
-var expect = '';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
- 
-  expect = 'No Error';
-  actual = 'No Error';
-  try
-  {
-    function f() { let k = 3; function g() { print(k); } g() }
-    f();
-  }
-  catch(ex)
-  {
-    actual = ex + '';
-  }
-  reportCompare(expect, actual, summary + ': 1');
-
-  expect = 'No Error';
-  actual = 'No Error';
-  try
-  {
-    function h() { let k = 3; if (1) function g() { print(k); } g() }
-    h();
-  }
-  catch(ex)
-  {
-    actual = ex + '';
-  }
-  reportCompare(expect, actual, summary + ': 2');
-
-  expect = 'No Error';
-  actual = 'No Error';
-  try
-  {
-    function i() { let k = 3; (function() { print(k); })() }
-    i();
-  }
-  catch(ex)
-  {
-    actual = ex + '';
-  }
-  reportCompare(expect, actual, summary + ': 3');
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-358508.js b/js/src/tests/js1_7/block/regress-358508.js
deleted file mode 100644
index 4b33db1fefa..00000000000
--- a/js/src/tests/js1_7/block/regress-358508.js
+++ /dev/null
@@ -1,37 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 358508;
-var summary = 'destructuring-parameters and block local functions';
-var actual = 'No Crash';
-var expect = 'No Crash';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
- 
-  try
-  {
-    (function({0x100000badf00d0: a}) {
-      function b() {}
-      let c;
-    })();
-  }
-  catch(ex)
-  {
-  }
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-376410.js b/js/src/tests/js1_7/block/regress-376410.js
deleted file mode 100644
index 501bcda64ec..00000000000
--- a/js/src/tests/js1_7/block/regress-376410.js
+++ /dev/null
@@ -1,37 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 376410;
-var summary = 'let declaration must be direct child of block, ' + 
-  'top-level implicit block, or switch body block';
-var actual = '';
-var expect = 'SyntaxError';
-
-// See https://bugzilla.mozilla.org/show_bug.cgi?id=408957
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
-
-  try
-  {
-    eval('(function() { while(0) L: let x; print(x); })');
-  }
-  catch(ex)
-  {
-    actual = ex.name;
-  }
- 
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/regress-396900.js b/js/src/tests/js1_7/block/regress-396900.js
deleted file mode 100644
index 9665b4159c6..00000000000
--- a/js/src/tests/js1_7/block/regress-396900.js
+++ /dev/null
@@ -1,31 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 396900;
-var summary = 'Destructuring bind in a let';
-var actual = '';
-var expect = '';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
- 
-  expect = '3, 4';
-  let ([x, y] = [3, 4]) { actual = x + ', ' + y}
-  reportCompare(expect, actual, summary);
-
-  expect = 'undefined, undefined';
-  actual = typeof x + ', ' + typeof y;
-  reportCompare(expect, actual, summary);
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/block/shell.js b/js/src/tests/js1_7/block/shell.js
deleted file mode 100644
index e69de29bb2d..00000000000
diff --git a/js/src/tests/js1_7/extensions/regress-349619.js b/js/src/tests/js1_7/extensions/regress-349619.js
deleted file mode 100644
index 834bb565f6f..00000000000
--- a/js/src/tests/js1_7/extensions/regress-349619.js
+++ /dev/null
@@ -1,28 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 349619;
-var summary = 'Do not assert with let block, object literal getter/setter';
-var actual = 'No Crash';
-var expect = 'No Crash';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
- 
-  (function() { let(y=3) { ({ get y() { }, set y(z) { } }) } });
-
-  reportCompare(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/extensions/regress-366668-02.js b/js/src/tests/js1_7/extensions/regress-366668-02.js
deleted file mode 100644
index 37e5567901b..00000000000
--- a/js/src/tests/js1_7/extensions/regress-366668-02.js
+++ /dev/null
@@ -1,31 +0,0 @@
-/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-//-----------------------------------------------------------------------------
-var BUGNUMBER = 366668;
-var summary = 'decompilation of "let with with" ';
-var actual = '';
-var expect = '';
-
-
-//-----------------------------------------------------------------------------
-test();
-//-----------------------------------------------------------------------------
-
-function test()
-{
-  enterFunc ('test');
-  printBugNumber(BUGNUMBER);
-  printStatus (summary);
- 
-  var f;
-
-  f = function() { let (w) { with({x: w.something }) { } } };
-  expect = 'function() { let (w) { with({x: w.something }) { } } }';
-  actual = f + '';
-  compareSource(expect, actual, summary);
-
-  exitFunc ('test');
-}
diff --git a/js/src/tests/js1_7/regress/regress-353079.js b/js/src/tests/js1_7/regress/regress-353079.js
index d0e32ad8be1..2c7fd015f22 100644
--- a/js/src/tests/js1_7/regress/regress-353079.js
+++ b/js/src/tests/js1_7/regress/regress-353079.js
@@ -20,8 +20,8 @@ function test()
   printBugNumber(BUGNUMBER);
   printStatus (summary);
  
-  for (let a in [1]) let (x) {
-    for (let y in ((function(id2) { return id2; })( '' ))) { } }
+  for (let a in [1]) { { let x;
+    for (let y in ((function(id2) { return id2; })( '' ))) { } } }
 
   reportCompare(expect, actual, summary);
 
diff --git a/js/src/tests/js1_7/regress/regress-355832-01.js b/js/src/tests/js1_7/regress/regress-355832-01.js
index c6a7e6f3b13..dccf7e832bd 100644
--- a/js/src/tests/js1_7/regress/regress-355832-01.js
+++ b/js/src/tests/js1_7/regress/regress-355832-01.js
@@ -22,7 +22,7 @@ function test()
  
   expect = actual = 'No Crash';
 
-  let ([] = []) { }
+  { let [] = []; }
 
   reportCompare(expect, actual, summary);
 
diff --git a/js/src/tests/js1_7/regress/regress-355832-02.js b/js/src/tests/js1_7/regress/regress-355832-02.js
index 84bc9ade79f..54e1506e42f 100644
--- a/js/src/tests/js1_7/regress/regress-355832-02.js
+++ b/js/src/tests/js1_7/regress/regress-355832-02.js
@@ -22,7 +22,7 @@ function test()
  
   expect = actual = 'No Crash';
 
-  let ([] = []) { print(3) } print(4)
+  { let [] = []; print(3) } print(4)
 
 			       reportCompare(expect, actual, summary);
 
diff --git a/js/src/tests/js1_7/regress/regress-373827-01.js b/js/src/tests/js1_7/regress/regress-373827-01.js
index be804c41dc2..01da279f85a 100644
--- a/js/src/tests/js1_7/regress/regress-373827-01.js
+++ b/js/src/tests/js1_7/regress/regress-373827-01.js
@@ -20,7 +20,7 @@ function test()
   printBugNumber(BUGNUMBER);
   printStatus (summary);
  
-  let ([] = [{x: function(){}}]) { };
+  { let [] = [{x: function(){}}]; };
 
   reportCompare(expect, actual, summary);
 
diff --git a/js/src/tests/js1_7/regress/regress-373827-02.js b/js/src/tests/js1_7/regress/regress-373827-02.js
index 55272aa187f..3596feb6944 100644
--- a/js/src/tests/js1_7/regress/regress-373827-02.js
+++ b/js/src/tests/js1_7/regress/regress-373827-02.js
@@ -22,7 +22,7 @@ function test()
  
   try
   {
-    let ([] = [{x: function(){}}]) { }; foo;
+    { let [] = [{x: function(){}}]; }; foo;
   }
   catch(ex)
   {
diff --git a/js/src/tests/js1_7/regress/regress-414553.js b/js/src/tests/js1_7/regress/regress-414553.js
index 6a1530fd95a..6f513902272 100644
--- a/js/src/tests/js1_7/regress/regress-414553.js
+++ b/js/src/tests/js1_7/regress/regress-414553.js
@@ -16,7 +16,8 @@ var actual = String([a,b,c,d]);
 reportCompare(expected, actual, 'destructuring assignment in let');
 
 function f() {
-  let (a = 1, [b,c] = [2,3], d = 4) {
+  {
+    let a = 1, [b,c] = [2,3], d = 4;
     return String([a,b,c,d]);
   }
 }
diff --git a/js/src/tests/js1_8/regress/regress-471660.js b/js/src/tests/js1_8/regress/regress-471660.js
index 3a8f106edd6..b09b0e7fcc8 100644
--- a/js/src/tests/js1_8/regress/regress-471660.js
+++ b/js/src/tests/js1_8/regress/regress-471660.js
@@ -26,7 +26,7 @@ function test()
 
   for (var w = 0; w < 5; ++w) {
 
-    let (y) { do break ; while (true); }
+    { let y; do break ; while (true); }
     for each (let x in [{}, function(){}]) {y}
 
   }
diff --git a/js/src/tests/js1_8_1/regress/regress-452498-050.js b/js/src/tests/js1_8_1/regress/regress-452498-050.js
index 77f0a50c455..309242a6241 100644
--- a/js/src/tests/js1_8_1/regress/regress-452498-050.js
+++ b/js/src/tests/js1_8_1/regress/regress-452498-050.js
@@ -25,7 +25,7 @@ function test()
 // Do not crash
 
 // compiler bug when a block introduces no names
-  let ({}={}) {}
+  { let {}={}; }
 
   try
   {
diff --git a/js/src/tests/js1_8_1/regress/regress-452498-053.js b/js/src/tests/js1_8_1/regress/regress-452498-053.js
index 6c053a5fdc5..9f70a0f7488 100644
--- a/js/src/tests/js1_8_1/regress/regress-452498-053.js
+++ b/js/src/tests/js1_8_1/regress/regress-452498-053.js
@@ -30,7 +30,7 @@ function test()
 //    JS_SetReservedSlot(cx, blockObj, index, PRIVATE_TO_JSVAL(pn));
 // but this uses reserved slots as though they were unlimited.
 // blockObj only has 2.
-  let (a=0, b=1, c=2) {}
+  { let a=0, b=1, c=2; }
 
 // In RecycleTree at ../jsparse.cpp:315, we hit
 //     MOZ_CRASH("RecycleUseDefKids");
diff --git a/js/src/tests/js1_8_1/regress/regress-496922.js b/js/src/tests/js1_8_1/regress/regress-496922.js
index f1d1903a5bf..fdc33e90a2d 100644
--- a/js/src/tests/js1_8_1/regress/regress-496922.js
+++ b/js/src/tests/js1_8_1/regress/regress-496922.js
@@ -19,8 +19,8 @@ printStatus (summary);
 jit(true);
 
 var a = [];
-let(
-f = function() {
+{
+let f = function() {
     for (let x = 0; x < 4; ++x) {
         (function() {
             for (let y = 0; y < 2; ++y) {
@@ -28,7 +28,7 @@ f = function() {
             }
         })()
     }
-}) { (function() {})()
+}; (function() {})()
     f(99)
 }
 actual = '' + a;
diff --git a/js/src/tests/js1_8_1/regress/regress-522123.js b/js/src/tests/js1_8_1/regress/regress-522123.js
index c78d07030b5..7a491e094e7 100644
--- a/js/src/tests/js1_8_1/regress/regress-522123.js
+++ b/js/src/tests/js1_8_1/regress/regress-522123.js
@@ -25,7 +25,8 @@ function test()
   expect = 1;
 
   evil=eval;
-  let (x=2) {
+  {
+    let x=2;
     actual = evil("x");
   };
 
diff --git a/js/src/tests/js1_8_1/strict/let-block-eval-arguments.js b/js/src/tests/js1_8_1/strict/let-block-eval-arguments.js
deleted file mode 100644
index d68e9b4e802..00000000000
--- a/js/src/tests/js1_8_1/strict/let-block-eval-arguments.js
+++ /dev/null
@@ -1,35 +0,0 @@
-// |reftest| skip-if(Android)
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-
-/*
- * Any copyright is dedicated to the Public Domain.
- * http://creativecommons.org/licenses/publicdomain/
- */
-
-/* In strict mode, a 'let' block may not bind 'eval' or 'arguments'. */
-assertEq(testLenientAndStrict('let (eval=1) {}',
-                              parsesSuccessfully,
-                              parseRaisesException(SyntaxError)),
-         true);
-assertEq(testLenientAndStrict('let ([eval]=1) {}',
-                              parsesSuccessfully,
-                              parseRaisesException(SyntaxError)),
-         true);
-assertEq(testLenientAndStrict('let ({x:eval}=1) {}',
-                              parsesSuccessfully,
-                              parseRaisesException(SyntaxError)),
-         true);
-assertEq(testLenientAndStrict('let (arguments=1) {}',
-                              parsesSuccessfully,
-                              parseRaisesException(SyntaxError)),
-         true);
-assertEq(testLenientAndStrict('let ([arguments]=1) {}',
-                              parsesSuccessfully,
-                              parseRaisesException(SyntaxError)),
-         true);
-assertEq(testLenientAndStrict('let ({x:arguments}=1) {}',
-                              parsesSuccessfully,
-                              parseRaisesException(SyntaxError)),
-         true);
-
-reportCompare(true, true);
diff --git a/js/src/tests/js1_8_5/reflect-parse/lexicals.js b/js/src/tests/js1_8_5/reflect-parse/lexicals.js
index 500e5bece14..c42c43c32f3 100644
--- a/js/src/tests/js1_8_5/reflect-parse/lexicals.js
+++ b/js/src/tests/js1_8_5/reflect-parse/lexicals.js
@@ -14,29 +14,6 @@ assertBlockDecl("let {x:y} = foo;", letDecl([{ id: objPatt([assignProp("x", iden
 assertDecl("const {x:y} = foo;", constDecl([{ id: objPatt([assignProp("x", ident("y"))]),
                                               init: ident("foo") }]));
 
-// let statements
-
-assertStmt("let (x=1) { }", letStmt([{ id: ident("x"), init: lit(1) }], blockStmt([])));
-assertStmt("let (x=1,y=2) { }", letStmt([{ id: ident("x"), init: lit(1) },
-                                         { id: ident("y"), init: lit(2) }],
-                                        blockStmt([])));
-assertStmt("let (x=1,y=2,z=3) { }", letStmt([{ id: ident("x"), init: lit(1) },
-                                             { id: ident("y"), init: lit(2) },
-                                             { id: ident("z"), init: lit(3) }],
-                                            blockStmt([])));
-assertStmt("let (x) { }", letStmt([{ id: ident("x"), init: null }], blockStmt([])));
-assertStmt("let (x,y) { }", letStmt([{ id: ident("x"), init: null },
-                                     { id: ident("y"), init: null }],
-                                    blockStmt([])));
-assertStmt("let (x,y,z) { }", letStmt([{ id: ident("x"), init: null },
-                                       { id: ident("y"), init: null },
-                                       { id: ident("z"), init: null }],
-                                      blockStmt([])));
-assertStmt("let (x = 1, y = x) { }", letStmt([{ id: ident("x"), init: lit(1) },
-                                              { id: ident("y"), init: ident("x") }],
-                                             blockStmt([])));
-assertError("let (x = 1, x = 2) { }", TypeError);
-
 }
 
 runtest(test);
diff --git a/js/src/tests/js1_8_5/regress/regress-541255-3.js b/js/src/tests/js1_8_5/regress/regress-541255-3.js
index ec1ab791636..e352429b2c1 100644
--- a/js/src/tests/js1_8_5/regress/regress-541255-3.js
+++ b/js/src/tests/js1_8_5/regress/regress-541255-3.js
@@ -5,7 +5,7 @@
  */
 
 function f(y) {
-    eval("let (z=2, w=y) { (function () { w.p = 7; })(); }");
+    eval("{ let z=2, w=y; (function () { w.p = 7; })(); }");
 }
 var x = {};
 f(x);
diff --git a/js/src/tests/js1_8_5/regress/regress-554955-1.js b/js/src/tests/js1_8_5/regress/regress-554955-1.js
index 20bf980a37e..80c26b08806 100644
--- a/js/src/tests/js1_8_5/regress/regress-554955-1.js
+++ b/js/src/tests/js1_8_5/regress/regress-554955-1.js
@@ -8,7 +8,8 @@ function f(s) {
   eval(s);
   return function(a) {
     var d;
-    let (c = 3) {
+    {
+      let c = 3;
       d = function() { a; }; // force Block object to be cloned
       with({}) {}; // repel JägerMonkey
       return b; // lookup occurs in scope of Block
diff --git a/js/src/tests/js1_8_5/regress/regress-554955-3.js b/js/src/tests/js1_8_5/regress/regress-554955-3.js
index 821e55d2bd0..c4e1a60cee6 100644
--- a/js/src/tests/js1_8_5/regress/regress-554955-3.js
+++ b/js/src/tests/js1_8_5/regress/regress-554955-3.js
@@ -9,7 +9,8 @@ function f(s) {
     return function(a) {
         with({}) {}; // repel JägerMonkey
         eval(a);
-        let (c = 3) {
+        {
+            let c = 3;
             return b;
         };
     };
diff --git a/js/src/tests/js1_8_5/regress/regress-554955-4.js b/js/src/tests/js1_8_5/regress/regress-554955-4.js
index 922c7f243f9..09713c2f971 100644
--- a/js/src/tests/js1_8_5/regress/regress-554955-4.js
+++ b/js/src/tests/js1_8_5/regress/regress-554955-4.js
@@ -11,7 +11,8 @@ function f() {
         // purge for the JSOP_DEFVAR will not change the global's shape,
         // and the property cache entry will remain valid.
         eval(a);
-        let (c = 3) {
+        {
+            let c = 3;
             // This eval forces the block to be cloned, so its shape gets
             // used as the property cache key shape.
             eval('');
diff --git a/js/src/tests/js1_8_5/regress/regress-554955-6.js b/js/src/tests/js1_8_5/regress/regress-554955-6.js
index aa376a560fa..73faaefb05a 100644
--- a/js/src/tests/js1_8_5/regress/regress-554955-6.js
+++ b/js/src/tests/js1_8_5/regress/regress-554955-6.js
@@ -10,7 +10,8 @@ function f(a) {
   // not yet been marked as a delegate at this point, so no scope chain
   // purge takes place when it is extended.
   eval(a);
-  let (b=3) {
+  {
+    let b=3;
     // This eval causes the cloned block object to be added to the
     // scope chain. The block needs a unique shape: its parent call
     // could acquire bindings for anything without affecting the global
@@ -33,8 +34,10 @@ assertEq("local", f("var v='local'"));
 // Similarly,but with a doubly-nested block; make sure everyone gets marked.
 function f2(a) {
   eval(a);
-  let (b=3) {
-    let (c=4) {
+  {
+    let b=3;
+    {
+      let c=4;
       eval("");
       return v;
     };
diff --git a/js/src/tests/js1_8_5/regress/regress-673070-1.js b/js/src/tests/js1_8_5/regress/regress-673070-1.js
deleted file mode 100644
index b6158330515..00000000000
--- a/js/src/tests/js1_8_5/regress/regress-673070-1.js
+++ /dev/null
@@ -1,9 +0,0 @@
-// Any copyright is dedicated to the Public Domain.
-// http://creativecommons.org/licenses/publicdomain/
-
-var q = [2];
-let ([q] = eval("q")) {
-    assertEq(q, 2);
-}
-
-reportCompare(0, 0, 'ok');
diff --git a/js/src/tests/js1_8_5/regress/regress-673070-2.js b/js/src/tests/js1_8_5/regress/regress-673070-2.js
deleted file mode 100644
index 65529265ee6..00000000000
--- a/js/src/tests/js1_8_5/regress/regress-673070-2.js
+++ /dev/null
@@ -1,9 +0,0 @@
-// Any copyright is dedicated to the Public Domain.
-// http://creativecommons.org/licenses/publicdomain/
-
-var q = 1;
-let ([q] = [eval("q")]) {
-    assertEq(q, 1);
-}
-
-reportCompare(0, 0, 'ok');
diff --git a/js/src/vm/Interpreter.cpp b/js/src/vm/Interpreter.cpp
index b9d0b6447eb..fb99a95d8d2 100644
--- a/js/src/vm/Interpreter.cpp
+++ b/js/src/vm/Interpreter.cpp
@@ -4520,6 +4520,31 @@ js::SpreadCallOperation(JSContext* cx, HandleScript script, jsbytecode* pc, Hand
         return false;
     }
 
+    // Do our own checks for the callee being a function, as Invoke uses the
+    // expression decompiler to decompile the callee stack operand based on
+    // the number of arguments. Spread operations have the callee at sp - 3
+    // when not constructing, and sp - 4 when constructing.
+    if (callee.isPrimitive()) {
+        return ReportIsNotFunction(cx, callee, 2 + constructing,
+                                   constructing ? CONSTRUCT : NO_CONSTRUCT);
+    }
+
+    const Class* clasp = callee.toObject().getClass();
+    if (MOZ_UNLIKELY(clasp != &JSFunction::class_)) {
+#if JS_HAS_NO_SUCH_METHOD
+        if (MOZ_UNLIKELY(clasp != &js_NoSuchMethodClass)) {
+#endif
+
+            if (!callee.toObject().callHook()) {
+                return ReportIsNotFunction(cx, callee, 2 + constructing,
+                                           constructing ? CONSTRUCT : NO_CONSTRUCT);
+            }
+
+#if JS_HAS_NO_SUCH_METHOD
+        }
+#endif
+    }
+
 #ifdef DEBUG
     // The object must be an array with dense elements and no holes. Baseline's
     // optimized spread call stubs rely on this.
diff --git a/js/src/vm/Xdr.h b/js/src/vm/Xdr.h
index dfb751d1954..510097d36b6 100644
--- a/js/src/vm/Xdr.h
+++ b/js/src/vm/Xdr.h
@@ -29,11 +29,11 @@ namespace js {
  *
  *  https://developer.mozilla.org/en-US/docs/SpiderMonkey/Internals/Bytecode
  */
-static const uint32_t XDR_BYTECODE_VERSION_SUBTRAHEND = 316;
+static const uint32_t XDR_BYTECODE_VERSION_SUBTRAHEND = 317;
 static const uint32_t XDR_BYTECODE_VERSION =
     uint32_t(0xb973c0de - XDR_BYTECODE_VERSION_SUBTRAHEND);
 
-static_assert(JSErr_Limit == 419,
+static_assert(JSErr_Limit == 418,
               "GREETINGS, POTENTIAL SUBTRAHEND INCREMENTER! If you added or "
               "removed MSG_DEFs from js.msg, you should increment "
               "XDR_BYTECODE_VERSION_SUBTRAHEND and update this assertion's "
diff --git a/js/xpconnect/wrappers/AccessCheck.cpp b/js/xpconnect/wrappers/AccessCheck.cpp
index 72b46f172f5..bec9758f107 100644
--- a/js/xpconnect/wrappers/AccessCheck.cpp
+++ b/js/xpconnect/wrappers/AccessCheck.cpp
@@ -120,8 +120,7 @@ IsFrameId(JSContext* cx, JSObject* obj, jsid idArg)
         return false;
     }
 
-    nsCOMPtr<nsIDOMWindowCollection> col;
-    win->GetFrames(getter_AddRefs(col));
+    nsCOMPtr<nsIDOMWindowCollection> col = win->GetFrames();
     if (!col) {
         return false;
     }
diff --git a/layout/base/nsDocumentViewer.cpp b/layout/base/nsDocumentViewer.cpp
index 605ac73c9fc..00700e8c635 100644
--- a/layout/base/nsDocumentViewer.cpp
+++ b/layout/base/nsDocumentViewer.cpp
@@ -3777,9 +3777,9 @@ nsDocumentViewer::PrintPreview(nsIPrintSettings* aPrintSettings,
     return NS_ERROR_FAILURE;
   }
 
-  nsCOMPtr<nsIDOMDocument> domDoc;
-  aChildDOMWin->GetDocument(getter_AddRefs(domDoc));
-  nsCOMPtr<nsIDocument> doc = do_QueryInterface(domDoc);
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aChildDOMWin);
+  MOZ_ASSERT(window);
+  nsCOMPtr<nsIDocument> doc = window->GetDoc();
   NS_ENSURE_STATE(doc);
 
   nsAutoPtr<nsPrintEventDispatcher> beforeAndAfterPrint(
@@ -4349,9 +4349,9 @@ nsDocumentViewer::OnDonePrinting()
     if (mDeferredWindowClose) {
       mDeferredWindowClose = false;
       if (mContainer) {
-        nsCOMPtr<nsIDOMWindow> win = mContainer->GetWindow();
-        if (win)
+        if (nsCOMPtr<nsPIDOMWindow> win = do_QueryInterface(mContainer->GetWindow())) {
           win->Close();
+        }
       }
     } else if (mClosingWhilePrinting) {
       if (mDocument) {
diff --git a/layout/generic/nsPluginFrame.cpp b/layout/generic/nsPluginFrame.cpp
index f386c351eeb..cf8a4f24262 100644
--- a/layout/generic/nsPluginFrame.cpp
+++ b/layout/generic/nsPluginFrame.cpp
@@ -788,10 +788,9 @@ nsPluginFrame::GetRemoteTabChromeOffset()
 {
   LayoutDeviceIntPoint offset;
   if (XRE_IsContentProcess()) {
-    nsCOMPtr<nsIDOMWindow> window = do_QueryInterface(GetContent()->OwnerDoc()->GetWindow());
+    nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(GetContent()->OwnerDoc()->GetWindow());
     if (window) {
-      nsCOMPtr<nsIDOMWindow> topWindow;
-      window->GetTop(getter_AddRefs(topWindow));
+      nsCOMPtr<nsPIDOMWindow> topWindow = window->GetTop();
       if (topWindow) {
         dom::TabChild* tc = dom::TabChild::GetFrom(topWindow);
         if (tc) {
diff --git a/layout/printing/nsPrintEngine.cpp b/layout/printing/nsPrintEngine.cpp
index c58975e27db..9496c7285b3 100644
--- a/layout/printing/nsPrintEngine.cpp
+++ b/layout/printing/nsPrintEngine.cpp
@@ -790,13 +790,15 @@ nsPrintEngine::PrintPreview(nsIPrintSettings* aPrintSettings,
     return NS_ERROR_FAILURE;
   }
 
-  NS_ENSURE_STATE(aChildDOMWin);
-  nsCOMPtr<nsIDOMDocument> doc;
-  aChildDOMWin->GetDocument(getter_AddRefs(doc));
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aChildDOMWin);
+  NS_ENSURE_STATE(window);
+  nsCOMPtr<nsIDocument> doc = window->GetDoc();
   NS_ENSURE_STATE(doc);
+  nsCOMPtr<nsIDOMDocument> domDoc = do_QueryInterface(doc);
+  MOZ_ASSERT(domDoc);
 
   // Document is not busy -- go ahead with the Print Preview
-  return CommonPrint(true, aPrintSettings, aWebProgressListener, doc);
+  return CommonPrint(true, aPrintSettings, aWebProgressListener, domDoc);
 }
 
 //----------------------------------------------------------------------------------
@@ -3111,9 +3113,9 @@ nsPrintEngine::FindPrintObjectByDOMWin(nsPrintObject* aPO,
     return nullptr;
   }
 
-  nsCOMPtr<nsIDOMDocument> domDoc;
-  aDOMWin->GetDocument(getter_AddRefs(domDoc));
-  nsCOMPtr<nsIDocument> doc = do_QueryInterface(domDoc);
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aDOMWin);
+
+  nsCOMPtr<nsIDocument> doc = window->GetDoc();
   if (aPO->mDocument && aPO->mDocument->GetOriginalDocument() == doc) {
     return aPO;
   }
diff --git a/layout/svg/nsSVGOuterSVGFrame.cpp b/layout/svg/nsSVGOuterSVGFrame.cpp
index 53ae15326ad..a66986212c4 100644
--- a/layout/svg/nsSVGOuterSVGFrame.cpp
+++ b/layout/svg/nsSVGOuterSVGFrame.cpp
@@ -889,14 +889,13 @@ nsSVGOuterSVGFrame::IsRootOfReplacedElementSubDoc(nsIFrame **aEmbeddingFrame)
   if (!mContent->GetParent()) {
     // Our content is the document element
     nsCOMPtr<nsIDocShell> docShell = PresContext()->GetDocShell();
-    nsCOMPtr<nsIDOMWindow> window;
+    nsCOMPtr<nsPIDOMWindow> window;
     if (docShell) {
       window = docShell->GetWindow();
     }
 
     if (window) {
-      nsCOMPtr<nsIDOMElement> frameElement;
-      window->GetFrameElement(getter_AddRefs(frameElement));
+      nsCOMPtr<nsIDOMElement> frameElement = window->GetFrameElement();
       nsCOMPtr<nsIObjectLoadingContent> olc = do_QueryInterface(frameElement);
       if (olc) {
         // Our document is inside an HTML 'object', 'embed' or 'applet' element
diff --git a/layout/xul/nsXULPopupManager.cpp b/layout/xul/nsXULPopupManager.cpp
index 74089b3b0ba..3f757644b42 100644
--- a/layout/xul/nsXULPopupManager.cpp
+++ b/layout/xul/nsXULPopupManager.cpp
@@ -830,10 +830,10 @@ CheckCaretDrawingState()
     if (!window)
       return;
 
-    nsCOMPtr<nsIDOMDocument> domDoc;
-    nsCOMPtr<nsIDocument> focusedDoc;
-    window->GetDocument(getter_AddRefs(domDoc));
-    focusedDoc = do_QueryInterface(domDoc);
+    nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(window);
+    MOZ_ASSERT(piWindow);
+
+    nsCOMPtr<nsIDocument> focusedDoc = piWindow->GetDoc();
     if (!focusedDoc)
       return;
 
diff --git a/layout/xul/nsXULTooltipListener.cpp b/layout/xul/nsXULTooltipListener.cpp
index c5be5de2b5d..fb445694587 100644
--- a/layout/xul/nsXULTooltipListener.cpp
+++ b/layout/xul/nsXULTooltipListener.cpp
@@ -569,10 +569,7 @@ nsXULTooltipListener::FindTooltip(nsIContent* aTarget, nsIContent** aTooltip)
     return NS_OK;
   }
 
-  bool closed;
-  window->GetClosed(&closed);
-
-  if (closed) {
+  if (window->Closed()) {
     return NS_OK;
   }
 
diff --git a/media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.cpp b/media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.cpp
index e3cce080947..81028f16140 100644
--- a/media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.cpp
+++ b/media/webrtc/signaling/src/peerconnection/PeerConnectionImpl.cpp
@@ -686,13 +686,10 @@ PeerConnectionImpl::Initialize(PeerConnectionObserver& aObserver,
 
 #if !defined(MOZILLA_EXTERNAL_LINKAGE)
   nsAutoCString locationCStr;
-  nsIDOMLocation* location;
-  res = mWindow->GetLocation(&location);
 
-  if (location && NS_SUCCEEDED(res)) {
+  if (nsCOMPtr<nsIDOMLocation> location = mWindow->GetLocation()) {
     nsAutoString locationAStr;
     location->ToString(locationAStr);
-    location->Release();
 
     CopyUTF16toUTF8(locationAStr, locationCStr);
 #define HELLO_CLICKER_URL_START "https://hello.firefox.com/"
diff --git a/mobile/android/b2gdroid/app/src/main/java/org/mozilla/b2gdroid/SettingsMapper.java b/mobile/android/b2gdroid/app/src/main/java/org/mozilla/b2gdroid/SettingsMapper.java
index 5297bec6b89..e7ac3c44fc6 100644
--- a/mobile/android/b2gdroid/app/src/main/java/org/mozilla/b2gdroid/SettingsMapper.java
+++ b/mobile/android/b2gdroid/app/src/main/java/org/mozilla/b2gdroid/SettingsMapper.java
@@ -4,6 +4,7 @@
 
 package org.mozilla.b2gdroid;
 
+import java.io.ByteArrayOutputStream;
 import java.util.Hashtable;
 
 import org.json.JSONArray;
@@ -15,6 +16,9 @@ import android.content.Context;
 import android.database.ContentObserver;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
+import android.graphics.Canvas;
+import android.graphics.drawable.BitmapDrawable;
+import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.os.Handler;
 import android.provider.Settings.System;
@@ -166,7 +170,8 @@ class SettingsMapper extends ContentObserver implements GeckoEventListener {
         EventDispatcher.getInstance()
                        .registerGeckoThreadListener(this,
                                                     "Settings:Change",
-                                                    "Android:GetIMEI");
+                                                    "Android:GetIMEI",
+                                                    "Android:GetWallpaper");
 
         mContext.getContentResolver()
                 .registerContentObserver(System.CONTENT_URI,
@@ -197,7 +202,8 @@ class SettingsMapper extends ContentObserver implements GeckoEventListener {
         EventDispatcher.getInstance()
                        .unregisterGeckoThreadListener(this,
                                                       "Settings:Change",
-                                                      "Android:GetIMEI");
+                                                      "Android:GetIMEI",
+                                                      "Android:GetWallpaper");
         mGeckoSettings.clear();
         mGeckoSettings = null;
         mAndroidSettings.clear();
@@ -232,6 +238,43 @@ class SettingsMapper extends ContentObserver implements GeckoEventListener {
                 Log.wtf(LOGTAG, "Error getting IMEI", jsonEx);
             }
             EventDispatcher.sendResponse(message, ret);
+        } else if ("Android:GetWallpaper".equals(event)) {
+            WallpaperManager wpManager = WallpaperManager.getInstance(mContext);
+            Drawable drawable = wpManager.getDrawable();
+
+            // Convert the drawable to a base64 url, using a bitmap.
+            Bitmap bitmap = null;
+
+            if (drawable instanceof BitmapDrawable) {
+                BitmapDrawable bitmapDrawable = (BitmapDrawable) drawable;
+                if(bitmapDrawable.getBitmap() != null) {
+                    bitmap = bitmapDrawable.getBitmap();
+                }
+            }
+
+            if (drawable.getIntrinsicWidth() <= 0 || drawable.getIntrinsicHeight() <= 0) {
+                bitmap = Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888); // Single color bitmap will be created of 1x1 pixel
+            } else {
+                bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),
+                                             drawable.getIntrinsicHeight(),
+                                             Bitmap.Config.ARGB_8888);
+            }
+
+            Canvas canvas = new Canvas(bitmap);
+            drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
+            drawable.draw(canvas);
+            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
+            byte b [] = baos.toByteArray();
+            final String uri = "data:image/png;base64," + Base64.encodeToString(b, Base64.NO_WRAP);
+
+            JSONObject ret = new JSONObject();
+            try {
+                ret.put("wallpaper", uri);
+            } catch(Exception jsonEx) {
+                Log.wtf(LOGTAG, "Error getting Wallpaper", jsonEx);
+            }
+            EventDispatcher.sendResponse(message, ret);
         }
     }
 
diff --git a/mobile/android/b2gdroid/components/Setup.js b/mobile/android/b2gdroid/components/Setup.js
index 99b50883e87..fbc36994bfd 100644
--- a/mobile/android/b2gdroid/components/Setup.js
+++ b/mobile/android/b2gdroid/components/Setup.js
@@ -18,17 +18,41 @@ XPCOMUtils.defineLazyModuleGetter(this, "FileUtils",
 XPCOMUtils.defineLazyModuleGetter(this, "AppsUtils",
                                   "resource://gre/modules/AppsUtils.jsm");
 
+XPCOMUtils.defineLazyServiceGetter(this, "settings",
+                                   "@mozilla.org/settingsService;1",
+                                   "nsISettingsService");
+
 function debug() {
   dump("-*- B2GDroidSetup " + Array.slice(arguments) + "\n");
 }
 
-function B2GDroidSetup() { }
+function B2GDroidSetup() {
+  this.wrappedJSObject = this;
+  this.isFirstRun = true;
+}
 
 B2GDroidSetup.prototype = {
   classID:         Components.ID('{8bc88ef2-3aab-4e94-a40c-e2c80added2c}'),
   QueryInterface:  XPCOMUtils.generateQI([Ci.nsIObserver,
                                           Ci.nsISupportsWeakReference]),
 
+  // Returns a promise that resolves once we have set the wallpaper.image
+  // setting in sync with Android's wallpaper.
+  setWallpaper: function() {
+    if (!this.isFirstRun) {
+      return Promise.resolve();
+    }
+
+    debug("Getting wallpaper");
+
+    Cu.import("resource://gre/modules/Messaging.jsm");
+    return Messaging.sendRequestForResult({ type: "Android:GetWallpaper" })
+      .then(aData => {
+        settings.createLock().set("wallpaper.image", aData.wallpaper, null);
+        return Promise.resolve();
+      });
+  },
+
   getApk: function() {
     let registry = Cc["@mozilla.org/chrome/chrome-registry;1"]
                      .getService(Ci.nsIChromeRegistry);
@@ -225,6 +249,7 @@ B2GDroidSetup.prototype = {
     let branch = Services.prefs.getBranch("b2gdroid");
     if (!AppsUtils.isFirstRun(branch)) {
       debug("No need to unpack gaia again.");
+      this.isFirstRun = false;
       return;
     }
 
diff --git a/mobile/android/chrome/content/browser.js b/mobile/android/chrome/content/browser.js
index 2c6a7212751..b4aa1cbaf03 100644
--- a/mobile/android/chrome/content/browser.js
+++ b/mobile/android/chrome/content/browser.js
@@ -5102,7 +5102,8 @@ var BrowserEventHandler = {
        * - It's a select element showing multiple rows
        */
       if (checkElem) {
-        if ((elem.scrollTopMax > 0 || elem.scrollLeftMax > 0) &&
+        if ((elem.scrollTopMin != elem.scrollTopMin ||
+             elem.scrollLeftMin != elem.scrollLeftMax) &&
             (this._hasScrollableOverflow(elem) ||
              elem.matches("textarea")) ||
             (elem instanceof HTMLInputElement && elem.mozIsTextField(false)) ||
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index 9c7fb684e8f..e62d67c4edd 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -152,7 +152,7 @@ pref("dom.serviceWorkers.enabled", false);
 pref("dom.serviceWorkers.interception.enabled", false);
 
 // Allow service workers to intercept opaque (cross origin) responses
-pref("dom.serviceWorkers.interception.opaque.enabled", false);
+pref("dom.serviceWorkers.interception.opaque.enabled", true);
 
 // The amount of time (milliseconds) service workers keep running after each event.
 pref("dom.serviceWorkers.idle_timeout", 30000);
@@ -561,6 +561,7 @@ pref("apz.fling_curve_function_x2", "1.0");
 pref("apz.fling_curve_function_y2", "1.0");
 pref("apz.fling_curve_threshold_inches_per_ms", "-1.0");
 pref("apz.fling_friction", "0.002");
+pref("apz.fling_snap_friction", "0.015");
 pref("apz.fling_stop_on_tap_threshold", "0.05");
 pref("apz.fling_stopped_threshold", "0.01");
 pref("apz.highlight_checkerboarded_areas", false);
diff --git a/netwerk/base/LoadInfo.cpp b/netwerk/base/LoadInfo.cpp
index 44867ee0692..ab4fc15cc40 100644
--- a/netwerk/base/LoadInfo.cpp
+++ b/netwerk/base/LoadInfo.cpp
@@ -74,10 +74,8 @@ LoadInfo::LoadInfo(nsIPrincipal* aLoadingPrincipal,
       mInnerWindowID = inner ? inner->WindowID() : 0;
       mOuterWindowID = outerWindow->WindowID();
 
-      nsCOMPtr<nsIDOMWindow> parent;
-      outerWindow->GetParent(getter_AddRefs(parent));
-      nsCOMPtr<nsPIDOMWindow> piParent = do_QueryInterface(parent);
-      mParentOuterWindowID = piParent->WindowID();
+      nsCOMPtr<nsPIDOMWindow> parent = outerWindow->GetParent();
+      mParentOuterWindowID = parent->WindowID();
     }
 
     mUpgradeInsecureRequests = aLoadingContext->OwnerDoc()->GetUpgradeInsecureRequests();
diff --git a/netwerk/protocol/http/Http2Session.cpp b/netwerk/protocol/http/Http2Session.cpp
index 18edfb0c0c9..e10ddabc1b6 100644
--- a/netwerk/protocol/http/Http2Session.cpp
+++ b/netwerk/protocol/http/Http2Session.cpp
@@ -3193,7 +3193,8 @@ Http2Session::OnWriteSegment(char *buf,
   }
 
   if (mDownstreamState == NOT_USING_NETWORK ||
-      mDownstreamState == BUFFERING_FRAME_HEADER) {
+      mDownstreamState == BUFFERING_FRAME_HEADER ||
+      mDownstreamState == DISCARDING_DATA_FRAME_PADDING) {
     return NS_BASE_STREAM_WOULD_BLOCK;
   }
 
@@ -3275,6 +3276,7 @@ Http2Session::OnWriteSegment(char *buf,
     return NS_OK;
   }
 
+  MOZ_ASSERT(false);
   return NS_ERROR_UNEXPECTED;
 }
 
diff --git a/netwerk/protocol/http/nsHttpHandler.cpp b/netwerk/protocol/http/nsHttpHandler.cpp
index 24bf31b4237..c04cfd995c9 100644
--- a/netwerk/protocol/http/nsHttpHandler.cpp
+++ b/netwerk/protocol/http/nsHttpHandler.cpp
@@ -2227,13 +2227,12 @@ nsHttpHandler::TickleWifi(nsIInterfaceRequestor *cb)
     // If B2G requires a similar mechanism nsINetworkManager, currently only avail
     // on B2G, contains the necessary information on wifi and gateway
 
-    nsCOMPtr<nsIDOMWindow> domWindow;
-    cb->GetInterface(NS_GET_IID(nsIDOMWindow), getter_AddRefs(domWindow));
-    if (!domWindow)
+    nsCOMPtr<nsIDOMWindow> domWindow = do_GetInterface(cb);
+    nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(domWindow);
+    if (!piWindow)
         return;
 
-    nsCOMPtr<nsIDOMNavigator> domNavigator;
-    domWindow->GetNavigator(getter_AddRefs(domNavigator));
+    nsCOMPtr<nsIDOMNavigator> domNavigator = piWindow->GetNavigator();
     nsCOMPtr<nsIMozNavigatorNetwork> networkNavigator =
         do_QueryInterface(domNavigator);
     if (!networkNavigator)
diff --git a/security/manager/pki/moz.build b/security/manager/pki/moz.build
index 0ae5748cc6f..a29e6ca6785 100644
--- a/security/manager/pki/moz.build
+++ b/security/manager/pki/moz.build
@@ -8,7 +8,6 @@ DIRS += ['resources']
 
 XPIDL_SOURCES += [
     'nsIASN1Tree.idl',
-    'nsIPKIParamBlock.idl',
 ]
 
 XPIDL_MODULE = 'pippki'
@@ -18,7 +17,6 @@ UNIFIED_SOURCES += [
     'nsNSSDialogHelper.cpp',
     'nsNSSDialogs.cpp',
     'nsPKIModule.cpp',
-    'nsPKIParamBlock.cpp',
 ]
 
 GENERATED_INCLUDES += [
diff --git a/security/manager/pki/nsIPKIParamBlock.idl b/security/manager/pki/nsIPKIParamBlock.idl
deleted file mode 100644
index df7180eeb14..00000000000
--- a/security/manager/pki/nsIPKIParamBlock.idl
+++ /dev/null
@@ -1,14 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
- *
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "nsISupports.idl"
-
-[scriptable, uuid(b6fe3d78-1dd1-11b2-9058-ced9016984c8)]
-interface nsIPKIParamBlock : nsISupports {
-
-  void setISupportAtIndex(in long index, in nsISupports object);
-  nsISupports getISupportAtIndex(in long index);
-};
diff --git a/security/manager/pki/nsNSSDialogHelper.cpp b/security/manager/pki/nsNSSDialogHelper.cpp
index 5e7e2e74889..6535cdf3dbd 100644
--- a/security/manager/pki/nsNSSDialogHelper.cpp
+++ b/security/manager/pki/nsNSSDialogHelper.cpp
@@ -5,23 +5,19 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "nsNSSDialogHelper.h"
-#include "nsIWindowWatcher.h"
-#include "nsCOMPtr.h"
-#include "nsIComponentManager.h"
-#include "nsIServiceManager.h"
-#include "nsIInterfaceRequestor.h"
-#include "nsIInterfaceRequestorUtils.h"
+
 #include "mozilla/dom/ScriptSettings.h"
+#include "nsCOMPtr.h"
+#include "nsIDOMWindow.h"
+#include "nsIServiceManager.h"
+#include "nsIWindowWatcher.h"
 
 static const char kOpenDialogParam[] = "centerscreen,chrome,modal,titlebar";
 static const char kOpenWindowParam[] = "centerscreen,chrome,titlebar";
 
 nsresult
-nsNSSDialogHelper::openDialog(
-    nsIDOMWindow *window,
-    const char *url,
-    nsISupports *params,
-    bool modal)
+nsNSSDialogHelper::openDialog(nsIDOMWindow* window, const char* url,
+                              nsISupports* params, bool modal)
 {
 #ifdef MOZ_WIDGET_GONK
   // On b2g devices, we need to proxy the dialog creation & management
@@ -58,4 +54,3 @@ nsNSSDialogHelper::openDialog(
                                  getter_AddRefs(newWindow));
   return rv;
 }
-
diff --git a/security/manager/pki/nsNSSDialogHelper.h b/security/manager/pki/nsNSSDialogHelper.h
index 488e532eb56..30868d825f9 100644
--- a/security/manager/pki/nsNSSDialogHelper.h
+++ b/security/manager/pki/nsNSSDialogHelper.h
@@ -7,7 +7,8 @@
 #ifndef nsNSSDialogHelper_h
 #define nsNSSDialogHelper_h
 
-#include "nsIDOMWindow.h"
+class nsIDOMWindow;
+class nsISupports;
 
 /**
  * Common class that uses the window watcher service to open a
@@ -18,13 +19,9 @@
 class nsNSSDialogHelper
 {
 public:
-  //The params is going to be either a nsIPKIParamBlock or
-  //nsIDialogParamBlock
-  static nsresult openDialog(
-                  nsIDOMWindow *window,
-                  const char *url,
-                  nsISupports *params,
-                  bool modal = true);
+  // params is a nsIDialogParamBlock or a nsIKeygenThread
+  static nsresult openDialog(nsIDOMWindow* window, const char* url,
+                             nsISupports* params, bool modal = true);
 };
 
 #endif
diff --git a/security/manager/pki/nsNSSDialogs.cpp b/security/manager/pki/nsNSSDialogs.cpp
index e1d04b8b91f..e31988aa967 100644
--- a/security/manager/pki/nsNSSDialogs.cpp
+++ b/security/manager/pki/nsNSSDialogs.cpp
@@ -25,7 +25,6 @@
 #include "nsPromiseFlatString.h"
 
 #include "nsNSSDialogs.h"
-#include "nsPKIParamBlock.h"
 #include "nsIKeygenThread.h"
 #include "nsIProtectedAuthThread.h"
 #include "nsNSSDialogHelper.h"
@@ -111,30 +110,36 @@ nsNSSDialogs::ConfirmDownloadCACert(nsIInterfaceRequestor *ctx,
 {
   nsresult rv;
 
-  *_retval = true;
+  nsCOMPtr<nsIMutableArray> dlgArray(do_CreateInstance(NS_ARRAY_CONTRACTID));
+  if (!dlgArray) {
+    return NS_ERROR_FAILURE;
+  }
+  rv = dlgArray->AppendElement(cert, false);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  nsCOMPtr<nsIDialogParamBlock> dlgParamBlock(
+    do_CreateInstance(NS_DIALOGPARAMBLOCK_CONTRACTID));
+  if (!dlgParamBlock) {
+    return NS_ERROR_FAILURE;
+  }
+  rv = dlgParamBlock->SetObjects(dlgArray);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
 
   // Get the parent window for the dialog
   nsCOMPtr<nsIDOMWindow> parent = do_GetInterface(ctx);
-
-  nsCOMPtr<nsIPKIParamBlock> block =
-           do_CreateInstance(NS_PKIPARAMBLOCK_CONTRACTID);
-  if (!block)
-    return NS_ERROR_FAILURE;
-
-  rv = block->SetISupportAtIndex(1, cert);
-  if (NS_FAILED(rv))
-    return rv;
-
   rv = nsNSSDialogHelper::openDialog(parent, 
                                      "chrome://pippki/content/downloadcert.xul",
-                                     block);
-  if (NS_FAILED(rv)) return rv;
+                                     dlgParamBlock);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
 
   int32_t status;
   int32_t ssl, email, objsign;
 
-  nsCOMPtr<nsIDialogParamBlock> dlgParamBlock = do_QueryInterface(block);
-  
   rv = dlgParamBlock->GetInt(1, &status);
   if (NS_FAILED(rv)) return rv;
   rv = dlgParamBlock->GetInt(2, &ssl);
@@ -149,12 +154,11 @@ nsNSSDialogs::ConfirmDownloadCACert(nsIInterfaceRequestor *ctx,
   *_trust |= (email) ? nsIX509CertDB::TRUSTED_EMAIL : 0;
   *_trust |= (objsign) ? nsIX509CertDB::TRUSTED_OBJSIGN : 0;
 
-  *_retval = (status == 0)?false:true;
+  *_retval = (status != 0);
 
   return rv;
 }
 
-
 NS_IMETHODIMP 
 nsNSSDialogs::NotifyCACertExists(nsIInterfaceRequestor *ctx)
 {
@@ -378,28 +382,32 @@ nsNSSDialogs::GetPKCS12FilePassword(nsIInterfaceRequestor* ctx,
 }
 
 NS_IMETHODIMP 
-nsNSSDialogs::ViewCert(nsIInterfaceRequestor *ctx, 
-                       nsIX509Cert *cert)
+nsNSSDialogs::ViewCert(nsIInterfaceRequestor* ctx, nsIX509Cert* cert)
 {
-  nsresult rv;
-
-  nsCOMPtr<nsIPKIParamBlock> block =
-           do_CreateInstance(NS_PKIPARAMBLOCK_CONTRACTID);
-  if (!block)
+  nsCOMPtr<nsIMutableArray> dlgArray(do_CreateInstance(NS_ARRAY_CONTRACTID));
+  if (!dlgArray) {
     return NS_ERROR_FAILURE;
-
-  rv = block->SetISupportAtIndex(1, cert);
-  if (NS_FAILED(rv))
+  }
+  nsresult rv = dlgArray->AppendElement(cert, false);
+  if (NS_FAILED(rv)) {
     return rv;
+  }
+  nsCOMPtr<nsIDialogParamBlock> dlgParamBlock(
+    do_CreateInstance(NS_DIALOGPARAMBLOCK_CONTRACTID));
+  if (!dlgParamBlock) {
+    return NS_ERROR_FAILURE;
+  }
+  rv = dlgParamBlock->SetObjects(dlgArray);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
 
   // Get the parent window for the dialog
   nsCOMPtr<nsIDOMWindow> parent = do_GetInterface(ctx);
-
-  rv = nsNSSDialogHelper::openDialog(parent,
-                                     "chrome://pippki/content/certViewer.xul",
-                                     block,
-                                     false);
-  return rv;
+  return nsNSSDialogHelper::openDialog(parent,
+                                       "chrome://pippki/content/certViewer.xul",
+                                       dlgParamBlock,
+                                       false);
 }
 
 NS_IMETHODIMP
diff --git a/security/manager/pki/nsPKIModule.cpp b/security/manager/pki/nsPKIModule.cpp
index fb3af221d1b..25b1ba8637d 100644
--- a/security/manager/pki/nsPKIModule.cpp
+++ b/security/manager/pki/nsPKIModule.cpp
@@ -7,22 +7,18 @@
 #include "mozilla/ModuleUtils.h"
 
 #include "nsNSSDialogs.h"
-#include "nsPKIParamBlock.h"
 #include "nsASN1Tree.h"
 
 NS_GENERIC_FACTORY_CONSTRUCTOR_INIT(nsNSSDialogs, Init)
-NS_GENERIC_FACTORY_CONSTRUCTOR_INIT(nsPKIParamBlock, Init)
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsNSSASN1Tree)
 
 NS_DEFINE_NAMED_CID(NS_NSSDIALOGS_CID);
 NS_DEFINE_NAMED_CID(NS_NSSASN1OUTINER_CID);
-NS_DEFINE_NAMED_CID(NS_PKIPARAMBLOCK_CID);
 
 
 static const mozilla::Module::CIDEntry kPKICIDs[] = {
   { &kNS_NSSDIALOGS_CID, false, nullptr, nsNSSDialogsConstructor },
   { &kNS_NSSASN1OUTINER_CID, false, nullptr, nsNSSASN1TreeConstructor },
-  { &kNS_PKIPARAMBLOCK_CID, false, nullptr, nsPKIParamBlockConstructor },
   { nullptr }
 };
 
@@ -34,7 +30,6 @@ static const mozilla::Module::ContractIDEntry kPKIContracts[] = {
   { NS_TOKENDIALOGS_CONTRACTID, &kNS_NSSDIALOGS_CID },
   { NS_GENERATINGKEYPAIRINFODIALOGS_CONTRACTID, &kNS_NSSDIALOGS_CID },
   { NS_ASN1TREE_CONTRACTID, &kNS_NSSASN1OUTINER_CID },
-  { NS_PKIPARAMBLOCK_CONTRACTID, &kNS_PKIPARAMBLOCK_CID },
   { nullptr }
 };
 
diff --git a/security/manager/pki/nsPKIParamBlock.cpp b/security/manager/pki/nsPKIParamBlock.cpp
deleted file mode 100644
index 1a3885fab8f..00000000000
--- a/security/manager/pki/nsPKIParamBlock.cpp
+++ /dev/null
@@ -1,97 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
- *
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "nsPKIParamBlock.h"
-#include "nsIServiceManager.h"
-#include "nsIDialogParamBlock.h"
-#include "nsIMutableArray.h"
-
-NS_IMPL_ISUPPORTS(nsPKIParamBlock, nsIPKIParamBlock, nsIDialogParamBlock)
-
-nsPKIParamBlock::nsPKIParamBlock()
-{
-}
-
-nsresult
-nsPKIParamBlock::Init()
-{
-  mDialogParamBlock = do_CreateInstance(NS_DIALOGPARAMBLOCK_CONTRACTID);
-  return !mDialogParamBlock ? NS_ERROR_OUT_OF_MEMORY : NS_OK;
-}
-
-nsPKIParamBlock::~nsPKIParamBlock()
-{
-}
-
-
-NS_IMETHODIMP 
-nsPKIParamBlock::SetNumberStrings( int32_t inNumStrings )
-{
-  return mDialogParamBlock->SetNumberStrings(inNumStrings);
-}
-
-NS_IMETHODIMP 
-nsPKIParamBlock::SetInt(int32_t inIndex, int32_t inInt)
-{
-  return mDialogParamBlock->SetInt(inIndex, inInt);
-}
-
-NS_IMETHODIMP 
-nsPKIParamBlock::GetInt(int32_t inIndex, int32_t *outInt)
-{
-  return mDialogParamBlock->GetInt(inIndex, outInt);
-}
-
-
-NS_IMETHODIMP 
-nsPKIParamBlock::GetString(int32_t inIndex, char16_t **_retval)
-{
-  return mDialogParamBlock->GetString(inIndex, _retval);
-}
-
-NS_IMETHODIMP 
-nsPKIParamBlock::SetString(int32_t inIndex, const char16_t *inString)
-{
-  return mDialogParamBlock->SetString(inIndex, inString);
-}
-
-NS_IMETHODIMP
-nsPKIParamBlock::GetObjects(nsIMutableArray * *aObjects)
-{
-  return mDialogParamBlock->GetObjects(aObjects);
-}
-
-NS_IMETHODIMP
-nsPKIParamBlock::SetObjects(nsIMutableArray * aObjects)
-{
-  return mDialogParamBlock->SetObjects(aObjects);
-}
-
-
-
-NS_IMETHODIMP 
-nsPKIParamBlock::SetISupportAtIndex(int32_t index, nsISupports *object)
-{
-  if (!mSupports) {
-    mSupports = do_CreateInstance(NS_SUPPORTSARRAY_CONTRACTID);
-    if (!mSupports) {
-      return NS_ERROR_OUT_OF_MEMORY;
-    }
-  }
-  // Ignore any InsertElementAt error, because this function always did that
-  mSupports->InsertElementAt(object, index-1);
-  return NS_OK;
-}
-
-NS_IMETHODIMP 
-nsPKIParamBlock::GetISupportAtIndex(int32_t index, nsISupports **_retval)
-{
-  NS_ENSURE_ARG(_retval);
-
-  return mSupports->GetElementAt(index - 1, _retval);
-}
-
-
diff --git a/security/manager/pki/nsPKIParamBlock.h b/security/manager/pki/nsPKIParamBlock.h
deleted file mode 100644
index 5b434455468..00000000000
--- a/security/manager/pki/nsPKIParamBlock.h
+++ /dev/null
@@ -1,36 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
- *
- * This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-#ifndef _NSPKIPARAMBLOCK_
-#define _NSPKIPARAMBLOCK_
-#include "nsCOMPtr.h"
-#include "nsIPKIParamBlock.h"
-#include "nsIDialogParamBlock.h"
-#include "nsISupportsArray.h"
-
-#define NS_PKIPARAMBLOCK_CID \
-  { 0x0bec75a8, 0x1dd2, 0x11b2, \
-    { 0x86, 0x3a, 0xf6, 0x9f, 0x77, 0xc3, 0x13, 0x71 }}
-
-#define NS_PKIPARAMBLOCK_CONTRACTID "@mozilla.org/security/pkiparamblock;1"
-
-class nsPKIParamBlock : public nsIPKIParamBlock,
-                        public nsIDialogParamBlock
-{
-public:
- 
-  nsPKIParamBlock();
-  nsresult Init();
-
-  NS_DECL_NSIPKIPARAMBLOCK
-  NS_DECL_NSIDIALOGPARAMBLOCK
-  NS_DECL_THREADSAFE_ISUPPORTS
-private:
-  virtual ~nsPKIParamBlock();
-  nsCOMPtr<nsIDialogParamBlock> mDialogParamBlock;
-  nsCOMPtr<nsISupportsArray>    mSupports;
-};
-
-#endif //_NSPKIPARAMBLOCK_
diff --git a/security/manager/pki/resources/content/certManager.js b/security/manager/pki/resources/content/certManager.js
index e8c83a6d6c0..e21d00daea0 100644
--- a/security/manager/pki/resources/content/certManager.js
+++ b/security/manager/pki/resources/content/certManager.js
@@ -11,8 +11,6 @@ const nsICertTree = Components.interfaces.nsICertTree;
 const nsCertTree = "@mozilla.org/security/nsCertTree;1";
 const nsIDialogParamBlock = Components.interfaces.nsIDialogParamBlock;
 const nsDialogParamBlock = "@mozilla.org/embedcomp/dialogparam;1";
-const nsIPKIParamBlock    = Components.interfaces.nsIPKIParamBlock;
-const nsPKIParamBlock    = "@mozilla.org/security/pkiparamblock;1";
 
 const gCertFileTypes = "*.p7b; *.crt; *.cert; *.cer; *.pem; *.der";
 
diff --git a/security/manager/pki/resources/content/deletecert.js b/security/manager/pki/resources/content/deletecert.js
index fb2c2867626..4a94ef52ec6 100644
--- a/security/manager/pki/resources/content/deletecert.js
+++ b/security/manager/pki/resources/content/deletecert.js
@@ -5,7 +5,6 @@
 const nsIX509Cert = Components.interfaces.nsIX509Cert;
 const nsX509CertDB = "@mozilla.org/security/x509certdb;1";
 const nsIX509CertDB = Components.interfaces.nsIX509CertDB;
-const nsIPKIParamBlock = Components.interfaces.nsIPKIParamBlock;
 const nsIDialogParamBlock = Components.interfaces.nsIDialogParamBlock;
 
 var certdb;
diff --git a/security/manager/pki/resources/content/downloadcert.js b/security/manager/pki/resources/content/downloadcert.js
index de844f94e07..8f486196536 100644
--- a/security/manager/pki/resources/content/downloadcert.js
+++ b/security/manager/pki/resources/content/downloadcert.js
@@ -3,20 +3,16 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 const nsIDialogParamBlock = Components.interfaces.nsIDialogParamBlock;
-const nsIPKIParamBlock = Components.interfaces.nsIPKIParamBlock;
 const nsIX509Cert = Components.interfaces.nsIX509Cert;
 
-var pkiParams;
 var params;
 var caName;
 var cert;
 
 function onLoad()
 {
-  pkiParams = window.arguments[0].QueryInterface(nsIPKIParamBlock);
-  params = pkiParams.QueryInterface(nsIDialogParamBlock);
-  var isupport = pkiParams.getISupportAtIndex(1);
-  cert = isupport.QueryInterface(nsIX509Cert);
+  params = window.arguments[0].QueryInterface(nsIDialogParamBlock);
+  cert = params.objects.queryElementAt(0, nsIX509Cert);
 
   caName = cert.commonName; 
 
diff --git a/security/manager/pki/resources/content/editcerts.js b/security/manager/pki/resources/content/editcerts.js
index dc3a620bf05..87ddf2a81cf 100644
--- a/security/manager/pki/resources/content/editcerts.js
+++ b/security/manager/pki/resources/content/editcerts.js
@@ -5,7 +5,6 @@
 const nsIX509Cert = Components.interfaces.nsIX509Cert;
 const nsX509CertDB = "@mozilla.org/security/x509certdb;1";
 const nsIX509CertDB = Components.interfaces.nsIX509CertDB;
-const nsIPKIParamBlock = Components.interfaces.nsIPKIParamBlock;
 
 var certdb;
 var cert;
diff --git a/security/manager/pki/resources/content/viewCertDetails.js b/security/manager/pki/resources/content/viewCertDetails.js
index eaca327b5ab..d36467df04f 100644
--- a/security/manager/pki/resources/content/viewCertDetails.js
+++ b/security/manager/pki/resources/content/viewCertDetails.js
@@ -7,12 +7,12 @@ const nsX509CertDB = "@mozilla.org/security/x509certdb;1";
 const nsIX509CertDB = Components.interfaces.nsIX509CertDB;
 const nsPK11TokenDB = "@mozilla.org/security/pk11tokendb;1";
 const nsIPK11TokenDB = Components.interfaces.nsIPK11TokenDB;
-const nsIPKIParamBlock = Components.interfaces.nsIPKIParamBlock;
 const nsIASN1Object = Components.interfaces.nsIASN1Object;
 const nsIASN1Sequence = Components.interfaces.nsIASN1Sequence;
 const nsIASN1PrintableItem = Components.interfaces.nsIASN1PrintableItem;
 const nsIASN1Tree = Components.interfaces.nsIASN1Tree;
 const nsASN1Tree = "@mozilla.org/security/nsASN1Tree;1"
+const nsIDialogParamBlock = Components.interfaces.nsIDialogParamBlock;
 
 var bundle;
 
@@ -78,9 +78,8 @@ function setWindowName()
     //var cert = certdb.findCertByNickname(token, myName);
     cert = certdb.findCertByNickname(null, myName);
   } else {
-    var pkiParams = window.arguments[0].QueryInterface(nsIPKIParamBlock);
-    var isupport = pkiParams.getISupportAtIndex(1);
-    cert = isupport.QueryInterface(nsIX509Cert);
+    var params = window.arguments[0].QueryInterface(nsIDialogParamBlock);
+    var cert = params.objects.queryElementAt(0, nsIX509Cert);
     document.title = certDetails + '"' + cert.windowTitle + '"'; // XXX l10n?
   }
 
diff --git a/testing/mochitest/runtests.py b/testing/mochitest/runtests.py
index c0734bc960f..e0e3e27a1f3 100644
--- a/testing/mochitest/runtests.py
+++ b/testing/mochitest/runtests.py
@@ -428,8 +428,8 @@ class MochitestServer(object):
         while i < timeout:
             if os.path.exists(aliveFile):
                 break
-            time.sleep(1)
-            i += 1
+            time.sleep(.05)
+            i += .05
         else:
             self._log.info(
                 "TEST-UNEXPECTED-FAIL | runtests.py | Timed out while waiting for server startup.")
diff --git a/testing/mozharness/mozharness/mozilla/building/hazards.py b/testing/mozharness/mozharness/mozilla/building/hazards.py
index 79bfb3efcc6..79e38d5f451 100644
--- a/testing/mozharness/mozharness/mozilla/building/hazards.py
+++ b/testing/mozharness/mozharness/mozilla/building/hazards.py
@@ -165,6 +165,8 @@ jobs = 4
                                     short_desc=short,
                                     long_desc=long,
                                     compress=True)
+        print("== Hazards (temporarily inline here, beware weirdly interleaved output, see bug 1211402) ==")
+        print(file(os.path.join(analysis_dir, "hazards.txt")).read())
 
     def upload_results(self, builder):
         """Upload the results of the analysis."""
diff --git a/toolkit/components/perfmonitoring/nsPerformanceStats.cpp b/toolkit/components/perfmonitoring/nsPerformanceStats.cpp
index d30beee0c41..aca248bf0d2 100644
--- a/toolkit/components/perfmonitoring/nsPerformanceStats.cpp
+++ b/toolkit/components/perfmonitoring/nsPerformanceStats.cpp
@@ -68,17 +68,17 @@ GetPrivateWindow(JSContext* cx) {
     return nullptr;
   }
 
-  nsCOMPtr<nsIDOMWindow> top;
-  nsresult rv = win->GetTop(getter_AddRefs(top));
-  if (!top || NS_FAILED(rv)) {
+  win = win->GetOuterWindow();
+  if (!win) {
     return nullptr;
   }
 
-  nsCOMPtr<nsPIDOMWindow> ptop = do_QueryInterface(top);
-  if (!ptop) {
+  nsCOMPtr<nsPIDOMWindow> top = win->GetTop();
+  if (!top) {
     return nullptr;
   }
-  return ptop.forget();
+
+  return top.forget();
 }
 
 bool
diff --git a/toolkit/components/satchel/nsFormFillController.cpp b/toolkit/components/satchel/nsFormFillController.cpp
index 2ca9fd56e67..bda4b07d507 100644
--- a/toolkit/components/satchel/nsFormFillController.cpp
+++ b/toolkit/components/satchel/nsFormFillController.cpp
@@ -101,8 +101,8 @@ nsFormFillController::~nsFormFillController()
   // Remove ourselves as a focus listener from all cached docShells
   uint32_t count = mDocShells.Length();
   for (uint32_t i = 0; i < count; ++i) {
-    nsCOMPtr<nsIDOMWindow> domWindow = GetWindowForDocShell(mDocShells[i]);
-    RemoveWindowListeners(domWindow);
+    nsCOMPtr<nsPIDOMWindow> window = GetWindowForDocShell(mDocShells[i]);
+    RemoveWindowListeners(window);
   }
 }
 
@@ -241,8 +241,8 @@ nsFormFillController::AttachToBrowser(nsIDocShell *aDocShell, nsIAutoCompletePop
   mPopups.AppendElement(aPopup);
 
   // Listen for focus events on the domWindow of the docShell
-  nsCOMPtr<nsIDOMWindow> domWindow = GetWindowForDocShell(aDocShell);
-  AddWindowListeners(domWindow);
+  nsCOMPtr<nsPIDOMWindow> window = GetWindowForDocShell(aDocShell);
+  AddWindowListeners(window);
 
   return NS_OK;
 }
@@ -254,9 +254,9 @@ nsFormFillController::DetachFromBrowser(nsIDocShell *aDocShell)
   NS_ENSURE_TRUE(index >= 0, NS_ERROR_FAILURE);
 
   // Stop listening for focus events on the domWindow of the docShell
-  nsCOMPtr<nsIDOMWindow> domWindow =
+  nsCOMPtr<nsPIDOMWindow> window =
     GetWindowForDocShell(mDocShells.SafeElementAt(index));
-  RemoveWindowListeners(domWindow);
+  RemoveWindowListeners(window);
 
   mDocShells.RemoveElementAt(index);
   mPopups.RemoveElementAt(index);
@@ -1080,15 +1080,12 @@ nsFormFillController::MouseDown(nsIDOMEvent* aEvent)
 //// nsFormFillController
 
 void
-nsFormFillController::AddWindowListeners(nsIDOMWindow *aWindow)
+nsFormFillController::AddWindowListeners(nsPIDOMWindow *aWindow)
 {
   if (!aWindow)
     return;
 
-  nsCOMPtr<nsPIDOMWindow> privateDOMWindow(do_QueryInterface(aWindow));
-  EventTarget* target = nullptr;
-  if (privateDOMWindow)
-    target = privateDOMWindow->GetChromeEventHandler();
+  EventTarget* target = aWindow->GetChromeEventHandler();
 
   if (!target)
     return;
@@ -1116,23 +1113,18 @@ nsFormFillController::AddWindowListeners(nsIDOMWindow *aWindow)
 }
 
 void
-nsFormFillController::RemoveWindowListeners(nsIDOMWindow *aWindow)
+nsFormFillController::RemoveWindowListeners(nsPIDOMWindow *aWindow)
 {
   if (!aWindow)
     return;
 
   StopControllingInput();
 
-  nsCOMPtr<nsIDOMDocument> domDoc;
-  aWindow->GetDocument(getter_AddRefs(domDoc));
-  nsCOMPtr<nsIDocument> doc = do_QueryInterface(domDoc);
+  nsCOMPtr<nsIDocument> doc = aWindow->GetDoc();
   PwmgrInputsEnumData ed(this, doc);
   mPwmgrInputs.Enumerate(RemoveForDocumentEnumerator, &ed);
 
-  nsCOMPtr<nsPIDOMWindow> privateDOMWindow(do_QueryInterface(aWindow));
-  EventTarget* target = nullptr;
-  if (privateDOMWindow)
-    target = privateDOMWindow->GetChromeEventHandler();
+  EventTarget* target = aWindow->GetChromeEventHandler();
 
   if (!target)
     return;
@@ -1227,7 +1219,7 @@ nsFormFillController::GetDocShellForInput(nsIDOMHTMLInputElement *aInput)
   return win->GetDocShell();
 }
 
-nsIDOMWindow *
+nsPIDOMWindow *
 nsFormFillController::GetWindowForDocShell(nsIDocShell *aDocShell)
 {
   nsCOMPtr<nsIContentViewer> contentViewer;
diff --git a/toolkit/components/satchel/nsFormFillController.h b/toolkit/components/satchel/nsFormFillController.h
index 76d58e5a59e..f859d18e091 100644
--- a/toolkit/components/satchel/nsFormFillController.h
+++ b/toolkit/components/satchel/nsFormFillController.h
@@ -16,7 +16,6 @@
 #include "nsCOMPtr.h"
 #include "nsDataHashtable.h"
 #include "nsIDocShell.h"
-#include "nsIDOMWindow.h"
 #include "nsIDOMHTMLInputElement.h"
 #include "nsILoginManager.h"
 #include "nsIMutationObserver.h"
@@ -30,6 +29,7 @@
 
 class nsFormHistory;
 class nsINode;
+class nsPIDOMWindow;
 
 class nsFormFillController final : public nsIFormFillController,
                                    public nsIAutoCompleteInput,
@@ -58,8 +58,8 @@ public:
 protected:
   virtual ~nsFormFillController();
 
-  void AddWindowListeners(nsIDOMWindow *aWindow);
-  void RemoveWindowListeners(nsIDOMWindow *aWindow);
+  void AddWindowListeners(nsPIDOMWindow *aWindow);
+  void RemoveWindowListeners(nsPIDOMWindow *aWindow);
 
   void AddKeyListener(nsINode* aInput);
   void RemoveKeyListener();
@@ -79,7 +79,7 @@ protected:
   bool RowMatch(nsFormHistory *aHistory, uint32_t aIndex, const nsAString &aInputName, const nsAString &aInputValue);
 
   inline nsIDocShell *GetDocShellForInput(nsIDOMHTMLInputElement *aInput);
-  inline nsIDOMWindow *GetWindowForDocShell(nsIDocShell *aDocShell);
+  inline nsPIDOMWindow *GetWindowForDocShell(nsIDocShell *aDocShell);
   inline int32_t GetIndexOfDocShell(nsIDocShell *aDocShell);
 
   void MaybeRemoveMutationObserver(nsINode* aNode);
diff --git a/toolkit/components/startup/nsAppStartup.cpp b/toolkit/components/startup/nsAppStartup.cpp
index b5baaa98ddb..dc40aa11eb9 100644
--- a/toolkit/components/startup/nsAppStartup.cpp
+++ b/toolkit/components/startup/nsAppStartup.cpp
@@ -433,11 +433,9 @@ nsAppStartup::Quit(uint32_t aMode)
             ferocity = eAttemptQuit;
             nsCOMPtr<nsISupports> window;
             windowEnumerator->GetNext(getter_AddRefs(window));
-            nsCOMPtr<nsIDOMWindow> domWindow = do_QueryInterface(window);
+            nsCOMPtr<nsPIDOMWindow> domWindow = do_QueryInterface(window);
             if (domWindow) {
-              bool closed = false;
-              domWindow->GetClosed(&closed);
-              if (!closed) {
+              if (!domWindow->Closed()) {
                 rv = NS_ERROR_FAILURE;
                 break;
               }
diff --git a/toolkit/content/browser-content.js b/toolkit/content/browser-content.js
index c1a689ebcf5..3f48d060c29 100644
--- a/toolkit/content/browser-content.js
+++ b/toolkit/content/browser-content.js
@@ -93,7 +93,7 @@ var ClickEventHandler = {
       // do not allow horizontal scrolling for select elements, it leads
       // to visual artifacts and is not the expected behavior anyway
       if (!(this._scrollable instanceof content.HTMLSelectElement) &&
-          this._scrollable.scrollLeftMax &&
+          this._scrollable.scrollLeftMin != this._scrollable.scrollLeftMax &&
           scrollingAllowed.indexOf(overflowx) >= 0) {
         this._scrolldir = scrollVert ? "NSEW" : "EW";
         break;
@@ -105,9 +105,10 @@ var ClickEventHandler = {
 
     if (!this._scrollable) {
       this._scrollable = aNode.ownerDocument.defaultView;
-      if (this._scrollable.scrollMaxX > 0) {
-        this._scrolldir = this._scrollable.scrollMaxY > 0 ? "NSEW" : "EW";
-      } else if (this._scrollable.scrollMaxY > 0) {
+      if (this._scrollable.scrollMaxX != this._scrollable.scrollMinX) {
+        this._scrolldir = this._scrollable.scrollMaxY !=
+                          this._scrollable.scrollMinY ? "NSEW" : "EW";
+      } else if (this._scrollable.scrollMaxY != this._scrollable.scrollMinY) {
         this._scrolldir = "NS";
       } else if (this._scrollable.frameElement) {
         this.findNearestScrollableElement(this._scrollable.frameElement);
diff --git a/toolkit/xre/ProfileReset.cpp b/toolkit/xre/ProfileReset.cpp
index 6a2d962880b..0c629e9bb1e 100644
--- a/toolkit/xre/ProfileReset.cpp
+++ b/toolkit/xre/ProfileReset.cpp
@@ -4,7 +4,6 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "nsIAppStartup.h"
-#include "nsIDOMWindow.h"
 #include "nsIFile.h"
 #include "nsIStringBundle.h"
 #include "nsIToolkitProfile.h"
@@ -14,6 +13,7 @@
 
 #include "nsDirectoryServiceDefs.h"
 #include "nsDirectoryServiceUtils.h"
+#include "nsPIDOMWindow.h"
 #include "nsPrintfCString.h"
 #include "nsToolkitCompsCID.h"
 #include "nsXPCOMCIDInternal.h"
@@ -164,7 +164,8 @@ ProfileResetCleanup(nsIToolkitProfile* aOldProfile)
     return rv;
   }
   // Close the progress window now that the cleanup thread is done.
-  progressWindow->Close();
+  nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(progressWindow);
+  piWindow->Close();
 
   // Delete the old profile from profiles.ini. The folder was already deleted by the thread above.
   rv = aOldProfile->Remove(false);
diff --git a/toolkit/xre/moz.build b/toolkit/xre/moz.build
index f68eafbb59e..d8127a6b984 100644
--- a/toolkit/xre/moz.build
+++ b/toolkit/xre/moz.build
@@ -82,14 +82,15 @@ UNIFIED_SOURCES += [
     'nsNativeAppSupportBase.cpp',
     'nsSigHandlers.cpp',
     'nsXREDirProvider.cpp',
-    'ProfileReset.cpp',
 ]
 
-# nsAppRunner.cpp cannot be built in unified mode because it pulls in OS X system headers.
+# nsAppRunner.cpp and ProfileReset.cpp cannot be built in unified mode because
+# they pull in OS X system headers.
 # nsEmbedFunctions.cpp cannot be built in unified mode because it pulls in X11 headers.
 SOURCES += [
     'nsAppRunner.cpp',
     'nsEmbedFunctions.cpp',
+    'ProfileReset.cpp',
 ]
 
 if CONFIG['MOZ_GL_DEFAULT_PROVIDER'] == 'GLX':
diff --git a/toolkit/xre/nsNativeAppSupportWin.cpp b/toolkit/xre/nsNativeAppSupportWin.cpp
index 2a05d5f5982..9e0c8d29b52 100644
--- a/toolkit/xre/nsNativeAppSupportWin.cpp
+++ b/toolkit/xre/nsNativeAppSupportWin.cpp
@@ -82,7 +82,8 @@ activateWindow( nsIDOMWindow *win ) {
         ::SetForegroundWindow( hwnd );
     } else {
         // Use internal method.
-        win->Focus();
+        nsCOMPtr<nsPIDOMWindow> piWin = do_QueryInterface(win);
+        piWin->Focus();
     }
 }
 
@@ -1021,8 +1022,7 @@ nsNativeAppSupportWin::HandleDDENotification( UINT uType,       // transaction t
                             break;
                         }
                         // Get location.
-                        nsCOMPtr<nsIDOMLocation> location;
-                        internalContent->GetLocation( getter_AddRefs( location ) );
+                        nsCOMPtr<nsIDOMLocation> location = internalContent->GetLocation();
                         if ( !location ) {
                             break;
                         }
diff --git a/uriloader/base/nsDocLoader.cpp b/uriloader/base/nsDocLoader.cpp
index e59e84e8a46..6f8af253a73 100644
--- a/uriloader/base/nsDocLoader.cpp
+++ b/uriloader/base/nsDocLoader.cpp
@@ -905,10 +905,7 @@ nsDocLoader::GetIsTopLevel(bool *aResult)
     nsCOMPtr<nsPIDOMWindow> piwindow = do_QueryInterface(window);
     NS_ENSURE_STATE(piwindow);
 
-    nsCOMPtr<nsIDOMWindow> topWindow;
-    nsresult rv = piwindow->GetTop(getter_AddRefs(topWindow));
-    NS_ENSURE_SUCCESS(rv, rv);
-
+    nsCOMPtr<nsPIDOMWindow> topWindow = piwindow->GetTop();
     *aResult = piwindow == topWindow;
   }
 
diff --git a/uriloader/exthandler/nsExternalHelperAppService.cpp b/uriloader/exthandler/nsExternalHelperAppService.cpp
index a799e7458fd..b440a88a603 100644
--- a/uriloader/exthandler/nsExternalHelperAppService.cpp
+++ b/uriloader/exthandler/nsExternalHelperAppService.cpp
@@ -2552,17 +2552,15 @@ bool nsExternalAppHandler::GetNeverAskFlagFromPref(const char * prefName, const
 
 nsresult nsExternalAppHandler::MaybeCloseWindow()
 {
-  nsCOMPtr<nsIDOMWindow> window = do_GetInterface(mContentContext);
+  nsCOMPtr<nsPIDOMWindow> window = do_GetInterface(mContentContext);
   NS_ENSURE_STATE(window);
 
   if (mShouldCloseWindow) {
     // Reset the window context to the opener window so that the dependent
     // dialogs have a parent
-    nsCOMPtr<nsIDOMWindow> opener;
-    window->GetOpener(getter_AddRefs(opener));
+    nsCOMPtr<nsPIDOMWindow> opener = window->GetOpener();
 
-    bool isClosed;
-    if (opener && NS_SUCCEEDED(opener->GetClosed(&isClosed)) && !isClosed) {
+    if (opener && !opener->Closed()) {
       mContentContext = do_GetInterface(opener);
 
       // Now close the old window.  Do it on a timer so that we don't run
@@ -2586,7 +2584,8 @@ nsExternalAppHandler::Notify(nsITimer* timer)
 {
   NS_ASSERTION(mWindowToClose, "No window to close after timer fired");
 
-  mWindowToClose->Close();
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(mWindowToClose);
+  window->Close();
   mWindowToClose = nullptr;
   mTimer = nullptr;
 
diff --git a/uriloader/prefetch/nsOfflineCacheUpdateService.cpp b/uriloader/prefetch/nsOfflineCacheUpdateService.cpp
index e1eef72ebf9..5eec45ecc51 100644
--- a/uriloader/prefetch/nsOfflineCacheUpdateService.cpp
+++ b/uriloader/prefetch/nsOfflineCacheUpdateService.cpp
@@ -201,8 +201,10 @@ nsOfflineCachePendingUpdate::OnStateChange(nsIWebProgress* aWebProgress,
     aWebProgress->GetDOMWindow(getter_AddRefs(window));
     if (!window) return NS_OK;
 
-    nsCOMPtr<nsIDOMDocument> progressDoc;
-    window->GetDocument(getter_AddRefs(progressDoc));
+    nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(window);
+    MOZ_ASSERT(piWindow);
+
+    nsCOMPtr<nsIDocument> progressDoc = piWindow->GetDoc();
     if (!progressDoc) return NS_OK;
 
     if (!SameCOMIdentity(progressDoc, updateDoc)) {
@@ -541,12 +543,12 @@ nsOfflineCacheUpdateService::Schedule(nsIURI *aManifestURI,
 
     nsresult rv;
 
-    if (aWindow) {
+    if (nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aWindow)) {
       // Ensure there is window.applicationCache object that is
       // responsible for association of the new applicationCache
       // with the corresponding document.  Just ignore the result.
-      nsCOMPtr<nsIDOMOfflineResourceList> appCacheWindowObject;
-      aWindow->GetApplicationCache(getter_AddRefs(appCacheWindowObject));
+      nsCOMPtr<nsIDOMOfflineResourceList> appCacheWindowObject =
+          window->GetApplicationCache();
     }
 
     rv = update->Init(aManifestURI, aDocumentURI, aLoadingPrincipal, aDocument,
diff --git a/widget/IMEData.h b/widget/IMEData.h
index c5c2e4c5ebc..a01e4af880c 100644
--- a/widget/IMEData.h
+++ b/widget/IMEData.h
@@ -554,6 +554,7 @@ struct IMENotification final
     bool mReversed;
     bool mCausedByComposition;
     bool mCausedBySelectionEvent;
+    bool mOccurredDuringComposition;
 
     void SetWritingMode(const WritingMode& aWritingMode);
     WritingMode GetWritingMode() const;
@@ -594,6 +595,7 @@ struct IMENotification final
       ClearSelectionData();
       mCausedByComposition = false;
       mCausedBySelectionEvent = false;
+      mOccurredDuringComposition = false;
     }
     bool IsValid() const
     {
@@ -606,13 +608,16 @@ struct IMENotification final
       mWritingMode = aOther.mWritingMode;
       mReversed = aOther.mReversed;
       AssignReason(aOther.mCausedByComposition,
-                   aOther.mCausedBySelectionEvent);
+                   aOther.mCausedBySelectionEvent,
+                   aOther.mOccurredDuringComposition);
     }
     void AssignReason(bool aCausedByComposition,
-                      bool aCausedBySelectionEvent)
+                      bool aCausedBySelectionEvent,
+                      bool aOccurredDuringComposition)
     {
       mCausedByComposition = aCausedByComposition;
       mCausedBySelectionEvent = aCausedBySelectionEvent;
+      mOccurredDuringComposition = aOccurredDuringComposition;
     }
   };
 
@@ -670,6 +675,7 @@ struct IMENotification final
     uint32_t mAddedEndOffset;
 
     bool mCausedByComposition;
+    bool mOccurredDuringComposition;
 
     uint32_t OldLength() const
     {
@@ -730,7 +736,8 @@ struct IMENotification final
     TextChangeData(uint32_t aStartOffset,
                    uint32_t aRemovedEndOffset,
                    uint32_t aAddedEndOffset,
-                   bool aCausedByComposition)
+                   bool aCausedByComposition,
+                   bool aOccurredDuringComposition)
     {
       MOZ_ASSERT(aRemovedEndOffset >= aStartOffset,
                  "removed end offset must not be smaller than start offset");
@@ -740,6 +747,7 @@ struct IMENotification final
       mRemovedEndOffset = aRemovedEndOffset;
       mAddedEndOffset = aAddedEndOffset;
       mCausedByComposition = aCausedByComposition;
+      mOccurredDuringComposition = aOccurredDuringComposition;
     }
   };
 
@@ -795,6 +803,18 @@ struct IMENotification final
         return false;
     }
   }
+
+  bool OccurredDuringComposition() const
+  {
+    switch (mMessage) {
+      case NOTIFY_IME_OF_SELECTION_CHANGE:
+        return mSelectionChangeData.mOccurredDuringComposition;
+      case NOTIFY_IME_OF_TEXT_CHANGE:
+        return mTextChangeData.mOccurredDuringComposition;
+      default:
+        return false;
+    }
+  }
 };
 
 } // namespace widget
diff --git a/widget/cocoa/moz.build b/widget/cocoa/moz.build
index 8ea66b9b231..aa8bfacd55d 100644
--- a/widget/cocoa/moz.build
+++ b/widget/cocoa/moz.build
@@ -87,6 +87,7 @@ FINAL_LIBRARY = 'xul'
 LOCAL_INCLUDES += [
     '/layout/forms',
     '/layout/generic',
+    '/layout/style',
     '/layout/xul',
     '/widget',
 ]
diff --git a/widget/cocoa/nsMenuItemIconX.mm b/widget/cocoa/nsMenuItemIconX.mm
index d76b29315ec..4f4cddbb8bc 100644
--- a/widget/cocoa/nsMenuItemIconX.mm
+++ b/widget/cocoa/nsMenuItemIconX.mm
@@ -26,7 +26,7 @@
 #include "nsNameSpaceManager.h"
 #include "nsGkAtoms.h"
 #include "nsIDOMElement.h"
-#include "nsIDOMCSSStyleDeclaration.h"
+#include "nsICSSDeclaration.h"
 #include "nsIDOMCSSValue.h"
 #include "nsIDOMCSSPrimitiveValue.h"
 #include "nsIDOMRect.h"
@@ -42,6 +42,7 @@
 #include "nsContentUtils.h"
 #include "nsIContentPolicy.h"
 
+using mozilla::dom::Element;
 using mozilla::gfx::SourceSurface;
 
 static const uint32_t kIconWidth = 16;
@@ -167,7 +168,7 @@ nsMenuItemIconX::GetIconURI(nsIURI** aIconURI)
 
   nsresult rv;
   nsCOMPtr<nsIDOMCSSValue> cssValue;
-  nsCOMPtr<nsIDOMCSSStyleDeclaration> cssStyleDecl;
+  nsCOMPtr<nsICSSDeclaration> cssStyleDecl;
   nsCOMPtr<nsIDOMCSSPrimitiveValue> primitiveValue;
   uint16_t primitiveType;
   if (!hasImageAttr) {
@@ -181,14 +182,19 @@ nsMenuItemIconX::GetIconURI(nsIURI** aIconURI)
     if (!window)
       return NS_ERROR_FAILURE;
 
-    nsCOMPtr<nsIDOMElement> domElement = do_QueryInterface(mContent);
+    window = window->GetCurrentInnerWindow();
+    if (!window)
+      return NS_ERROR_FAILURE;
+
+    nsCOMPtr<Element> domElement = do_QueryInterface(mContent);
     if (!domElement)
       return NS_ERROR_FAILURE;
 
-    rv = window->GetComputedStyle(domElement, EmptyString(),
-                                  getter_AddRefs(cssStyleDecl));
-    if (NS_FAILED(rv))
-      return rv;
+    ErrorResult dummy;
+    cssStyleDecl = window->GetComputedStyle(*domElement, EmptyString(), dummy);
+    dummy.SuppressException();
+    if (!cssStyleDecl)
+      return NS_ERROR_FAILURE;
 
     NS_NAMED_LITERAL_STRING(listStyleImage, "list-style-image");
     rv = cssStyleDecl->GetPropertyCSSValue(listStyleImage,
diff --git a/widget/gtk/IMContextWrapper.cpp b/widget/gtk/IMContextWrapper.cpp
index 966cf29aefc..6866a5e6b23 100644
--- a/widget/gtk/IMContextWrapper.cpp
+++ b/widget/gtk/IMContextWrapper.cpp
@@ -191,6 +191,7 @@ IMContextWrapper::IMContextWrapper(nsWindow* aOwnerWindow)
     , mIsDeletingSurrounding(false)
     , mLayoutChanged(false)
     , mSetCursorPositionOnKeyEvent(true)
+    , mPendingResettingIMContext(false)
 {
     if (!gGtkIMLog) {
         gGtkIMLog = PR_NewLogModule("nsGtkIMModuleWidgets");
@@ -564,6 +565,7 @@ IMContextWrapper::ResetIME()
     RefPtr<IMContextWrapper> kungFuDeathGrip(this);
     RefPtr<nsWindow> lastFocusedWindow(mLastFocusedWindow);
 
+    mPendingResettingIMContext = false;
     gtk_im_context_reset(activeContext);
 
     // The last focused window might have been destroyed by a DOM event handler
@@ -895,7 +897,8 @@ IMContextWrapper::OnSelectionChange(nsWindow* aCaller,
     MOZ_LOG(gGtkIMLog, LogLevel::Info,
         ("GTKIM: %p OnSelectionChange(aCaller=0x%p, aIMENotification={ "
          "mSelectionChangeData={ mOffset=%u, Length()=%u, mReversed=%s, "
-         "mWritingMode=%s, mCausedByComposition=%s, mCausedBySelectionEvent=%s "
+         "mWritingMode=%s, mCausedByComposition=%s, "
+         "mCausedBySelectionEvent=%s, mOccurredDuringComposition=%s "
          "} }), mCompositionState=%s, mIsDeletingSurrounding=%s",
          this, aCaller, selectionChangeData.mOffset,
          selectionChangeData.Length(),
@@ -903,6 +906,7 @@ IMContextWrapper::OnSelectionChange(nsWindow* aCaller,
          GetWritingModeName(selectionChangeData.GetWritingMode()).get(),
          ToChar(selectionChangeData.mCausedByComposition),
          ToChar(selectionChangeData.mCausedBySelectionEvent),
+         ToChar(selectionChangeData.mOccurredDuringComposition),
          GetCompositionStateName(), ToChar(mIsDeletingSurrounding)));
 
     if (aCaller != mLastFocusedWindow) {
@@ -950,11 +954,18 @@ IMContextWrapper::OnSelectionChange(nsWindow* aCaller,
         return;
     }
 
-    // When the selection change is caused by dispatching composition event
-    // and/or selection set event, we shouldn't notify IME of that and commit
-    // existing composition.
+    bool occurredBeforeComposition =
+      IsComposing() && !selectionChangeData.mOccurredDuringComposition;
+    if (occurredBeforeComposition) {
+        mPendingResettingIMContext = true;
+    }
+
+    // When the selection change is caused by dispatching composition event,
+    // selection set event and/or occurred before starting current composition,
+    // we shouldn't notify IME of that and commit existing composition.
     if (!selectionChangeData.mCausedByComposition &&
-        !selectionChangeData.mCausedBySelectionEvent) {
+        !selectionChangeData.mCausedBySelectionEvent &&
+        !occurredBeforeComposition) {
         ResetIME();
     }
 }
@@ -1022,13 +1033,17 @@ IMContextWrapper::OnEndCompositionNative(GtkIMContext* aContext)
     g_object_unref(mComposingContext);
     mComposingContext = nullptr;
 
-    if (!IsComposing()) {
-        // If we already handled the commit event, we should do nothing here.
-        return;
+    // If we already handled the commit event, we should do nothing here.
+    if (IsComposing()) {
+        if (!DispatchCompositionCommitEvent(aContext)) {
+            // If the widget is destroyed, we should do nothing anymore.
+            return;
+        }
     }
 
-    // Be aware, widget can be gone
-    DispatchCompositionCommitEvent(aContext);
+    if (mPendingResettingIMContext) {
+        ResetIME();
+    }
 }
 
 /* static */
diff --git a/widget/gtk/IMContextWrapper.h b/widget/gtk/IMContextWrapper.h
index aa3a745d2e6..41f95e497ac 100644
--- a/widget/gtk/IMContextWrapper.h
+++ b/widget/gtk/IMContextWrapper.h
@@ -263,6 +263,13 @@ protected:
     // with no composition.  If true, we update candidate window position
     // before key down
     bool mSetCursorPositionOnKeyEvent;
+    // mPendingResettingIMContext becomes true if selection change notification
+    // is received during composition but the selection change occurred before
+    // starting the composition.  In such case, we cannot notify IME of
+    // selection change during composition because we don't want to commit
+    // the composition in such case.  However, we should notify IME of the
+    // selection change after the composition is committed.
+    bool mPendingResettingIMContext;
 
     // sLastFocusedContext is a pointer to the last focused instance of this
     // class.  When a instance is destroyed and sLastFocusedContext refers it,
diff --git a/widget/nsBaseWidget.cpp b/widget/nsBaseWidget.cpp
index 421fab30686..f28cb81ca12 100644
--- a/widget/nsBaseWidget.cpp
+++ b/widget/nsBaseWidget.cpp
@@ -2031,8 +2031,14 @@ IMENotification::TextChangeDataBase::MergeWith(
   const TextChangeDataBase& newData = aOther;
   const TextChangeDataBase oldData = *this;
 
+  // mCausedByComposition should be true only when all changes are caused by
+  // composition.
   mCausedByComposition =
     newData.mCausedByComposition && oldData.mCausedByComposition;
+  // mOccurredDuringComposition should be true only when all changes occurred
+  // during composition.
+  mOccurredDuringComposition =
+    newData.mOccurredDuringComposition && oldData.mOccurredDuringComposition;
 
   if (newData.mStartOffset >= oldData.mAddedEndOffset) {
     // Case 1:
@@ -2188,8 +2194,8 @@ IMENotification::TextChangeDataBase::Test()
    ****************************************************************************/
 
   // Appending text
-  MergeWith(TextChangeData(10, 10, 20, false));
-  MergeWith(TextChangeData(20, 20, 35, false));
+  MergeWith(TextChangeData(10, 10, 20, false, false));
+  MergeWith(TextChangeData(20, 20, 35, false, false));
   MOZ_ASSERT(mStartOffset == 10,
     "Test 1-1-1: mStartOffset should be the first offset");
   MOZ_ASSERT(mRemovedEndOffset == 10, // 20 - (20 - 10)
@@ -2199,8 +2205,8 @@ IMENotification::TextChangeDataBase::Test()
   Clear();
 
   // Removing text (longer line -> shorter line)
-  MergeWith(TextChangeData(10, 20, 10, false));
-  MergeWith(TextChangeData(10, 30, 10, false));
+  MergeWith(TextChangeData(10, 20, 10, false, false));
+  MergeWith(TextChangeData(10, 30, 10, false, false));
   MOZ_ASSERT(mStartOffset == 10,
     "Test 1-2-1: mStartOffset should be the first offset");
   MOZ_ASSERT(mRemovedEndOffset == 40, // 30 + (10 - 20)
@@ -2211,8 +2217,8 @@ IMENotification::TextChangeDataBase::Test()
   Clear();
 
   // Removing text (shorter line -> longer line)
-  MergeWith(TextChangeData(10, 20, 10, false));
-  MergeWith(TextChangeData(10, 15, 10, false));
+  MergeWith(TextChangeData(10, 20, 10, false, false));
+  MergeWith(TextChangeData(10, 15, 10, false, false));
   MOZ_ASSERT(mStartOffset == 10,
     "Test 1-3-1: mStartOffset should be the first offset");
   MOZ_ASSERT(mRemovedEndOffset == 25, // 15 + (10 - 20)
@@ -2223,8 +2229,8 @@ IMENotification::TextChangeDataBase::Test()
   Clear();
 
   // Appending text at different point (not sure if actually occurs)
-  MergeWith(TextChangeData(10, 10, 20, false));
-  MergeWith(TextChangeData(55, 55, 60, false));
+  MergeWith(TextChangeData(10, 10, 20, false, false));
+  MergeWith(TextChangeData(55, 55, 60, false, false));
   MOZ_ASSERT(mStartOffset == 10,
     "Test 1-4-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 45, // 55 - (10 - 20)
@@ -2235,8 +2241,8 @@ IMENotification::TextChangeDataBase::Test()
   Clear();
 
   // Removing text at different point (not sure if actually occurs)
-  MergeWith(TextChangeData(10, 20, 10, false));
-  MergeWith(TextChangeData(55, 68, 55, false));
+  MergeWith(TextChangeData(10, 20, 10, false, false));
+  MergeWith(TextChangeData(55, 68, 55, false, false));
   MOZ_ASSERT(mStartOffset == 10,
     "Test 1-5-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 78, // 68 - (10 - 20)
@@ -2247,8 +2253,8 @@ IMENotification::TextChangeDataBase::Test()
   Clear();
 
   // Replacing text and append text (becomes longer)
-  MergeWith(TextChangeData(30, 35, 32, false));
-  MergeWith(TextChangeData(32, 32, 40, false));
+  MergeWith(TextChangeData(30, 35, 32, false, false));
+  MergeWith(TextChangeData(32, 32, 40, false, false));
   MOZ_ASSERT(mStartOffset == 30,
     "Test 1-6-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 35, // 32 - (32 - 35)
@@ -2259,8 +2265,8 @@ IMENotification::TextChangeDataBase::Test()
   Clear();
 
   // Replacing text and append text (becomes shorter)
-  MergeWith(TextChangeData(30, 35, 32, false));
-  MergeWith(TextChangeData(32, 32, 33, false));
+  MergeWith(TextChangeData(30, 35, 32, false, false));
+  MergeWith(TextChangeData(32, 32, 33, false, false));
   MOZ_ASSERT(mStartOffset == 30,
     "Test 1-7-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 35, // 32 - (32 - 35)
@@ -2272,8 +2278,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Removing text and replacing text after first range (not sure if actually
   // occurs)
-  MergeWith(TextChangeData(30, 35, 30, false));
-  MergeWith(TextChangeData(32, 34, 48, false));
+  MergeWith(TextChangeData(30, 35, 30, false, false));
+  MergeWith(TextChangeData(32, 34, 48, false, false));
   MOZ_ASSERT(mStartOffset == 30,
     "Test 1-8-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 39, // 34 - (30 - 35)
@@ -2285,8 +2291,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Removing text and replacing text after first range (not sure if actually
   // occurs)
-  MergeWith(TextChangeData(30, 35, 30, false));
-  MergeWith(TextChangeData(32, 38, 36, false));
+  MergeWith(TextChangeData(30, 35, 30, false, false));
+  MergeWith(TextChangeData(32, 38, 36, false, false));
   MOZ_ASSERT(mStartOffset == 30,
     "Test 1-9-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 43, // 38 - (30 - 35)
@@ -2302,8 +2308,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text in around end of added text (becomes shorter) (not sure
   // if actually occurs)
-  MergeWith(TextChangeData(50, 50, 55, false));
-  MergeWith(TextChangeData(53, 60, 54, false));
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(53, 60, 54, false, false));
   MOZ_ASSERT(mStartOffset == 50,
     "Test 2-1-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 55, // 60 - (55 - 50)
@@ -2315,8 +2321,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text around end of added text (becomes longer) (not sure
   // if actually occurs)
-  MergeWith(TextChangeData(50, 50, 55, false));
-  MergeWith(TextChangeData(54, 62, 68, false));
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(54, 62, 68, false, false));
   MOZ_ASSERT(mStartOffset == 50,
     "Test 2-2-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 57, // 62 - (55 - 50)
@@ -2328,8 +2334,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text around end of replaced text (became shorter) (not sure if
   // actually occurs)
-  MergeWith(TextChangeData(36, 48, 45, false));
-  MergeWith(TextChangeData(43, 50, 49, false));
+  MergeWith(TextChangeData(36, 48, 45, false, false));
+  MergeWith(TextChangeData(43, 50, 49, false, false));
   MOZ_ASSERT(mStartOffset == 36,
     "Test 2-3-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 53, // 50 - (45 - 48)
@@ -2341,8 +2347,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text around end of replaced text (became longer) (not sure if
   // actually occurs)
-  MergeWith(TextChangeData(36, 52, 53, false));
-  MergeWith(TextChangeData(43, 68, 61, false));
+  MergeWith(TextChangeData(36, 52, 53, false, false));
+  MergeWith(TextChangeData(43, 68, 61, false, false));
   MOZ_ASSERT(mStartOffset == 36,
     "Test 2-4-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 67, // 68 - (53 - 52)
@@ -2357,8 +2363,8 @@ IMENotification::TextChangeDataBase::Test()
    ****************************************************************************/
 
   // Appending text in already added text (not sure if actually occurs)
-  MergeWith(TextChangeData(10, 10, 20, false));
-  MergeWith(TextChangeData(15, 15, 30, false));
+  MergeWith(TextChangeData(10, 10, 20, false, false));
+  MergeWith(TextChangeData(15, 15, 30, false, false));
   MOZ_ASSERT(mStartOffset == 10,
     "Test 3-1-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 10,
@@ -2369,8 +2375,8 @@ IMENotification::TextChangeDataBase::Test()
   Clear();
 
   // Replacing text in added text (not sure if actually occurs)
-  MergeWith(TextChangeData(50, 50, 55, false));
-  MergeWith(TextChangeData(52, 53, 56, false));
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(52, 53, 56, false, false));
   MOZ_ASSERT(mStartOffset == 50,
     "Test 3-2-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 50,
@@ -2382,8 +2388,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text in replaced text (became shorter) (not sure if actually
   // occurs)
-  MergeWith(TextChangeData(36, 48, 45, false));
-  MergeWith(TextChangeData(37, 38, 50, false));
+  MergeWith(TextChangeData(36, 48, 45, false, false));
+  MergeWith(TextChangeData(37, 38, 50, false, false));
   MOZ_ASSERT(mStartOffset == 36,
     "Test 3-3-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 48,
@@ -2395,8 +2401,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text in replaced text (became longer) (not sure if actually
   // occurs)
-  MergeWith(TextChangeData(32, 48, 53, false));
-  MergeWith(TextChangeData(43, 50, 52, false));
+  MergeWith(TextChangeData(32, 48, 53, false, false));
+  MergeWith(TextChangeData(43, 50, 52, false, false));
   MOZ_ASSERT(mStartOffset == 32,
     "Test 3-4-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 48,
@@ -2409,8 +2415,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text in replaced text (became shorter) (not sure if actually
   // occurs)
-  MergeWith(TextChangeData(36, 48, 50, false));
-  MergeWith(TextChangeData(37, 49, 47, false));
+  MergeWith(TextChangeData(36, 48, 50, false, false));
+  MergeWith(TextChangeData(37, 49, 47, false, false));
   MOZ_ASSERT(mStartOffset == 36,
     "Test 3-5-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 48,
@@ -2423,8 +2429,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text in replaced text (became longer) (not sure if actually
   // occurs)
-  MergeWith(TextChangeData(32, 48, 53, false));
-  MergeWith(TextChangeData(43, 50, 47, false));
+  MergeWith(TextChangeData(32, 48, 53, false, false));
+  MergeWith(TextChangeData(43, 50, 47, false, false));
   MOZ_ASSERT(mStartOffset == 32,
     "Test 3-6-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 48,
@@ -2440,8 +2446,8 @@ IMENotification::TextChangeDataBase::Test()
    ****************************************************************************/
 
   // Replacing text all of already append text (not sure if actually occurs)
-  MergeWith(TextChangeData(50, 50, 55, false));
-  MergeWith(TextChangeData(44, 66, 68, false));
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(44, 66, 68, false, false));
   MOZ_ASSERT(mStartOffset == 44,
     "Test 4-1-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 61, // 66 - (55 - 50)
@@ -2453,8 +2459,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text around a point in which text was removed (not sure if
   // actually occurs)
-  MergeWith(TextChangeData(50, 62, 50, false));
-  MergeWith(TextChangeData(44, 66, 68, false));
+  MergeWith(TextChangeData(50, 62, 50, false, false));
+  MergeWith(TextChangeData(44, 66, 68, false, false));
   MOZ_ASSERT(mStartOffset == 44,
     "Test 4-2-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 78, // 66 - (50 - 62)
@@ -2466,8 +2472,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text all replaced text (became shorter) (not sure if actually
   // occurs)
-  MergeWith(TextChangeData(50, 62, 60, false));
-  MergeWith(TextChangeData(49, 128, 130, false));
+  MergeWith(TextChangeData(50, 62, 60, false, false));
+  MergeWith(TextChangeData(49, 128, 130, false, false));
   MOZ_ASSERT(mStartOffset == 49,
     "Test 4-3-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 130, // 128 - (60 - 62)
@@ -2479,8 +2485,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text all replaced text (became longer) (not sure if actually
   // occurs)
-  MergeWith(TextChangeData(50, 61, 73, false));
-  MergeWith(TextChangeData(44, 100, 50, false));
+  MergeWith(TextChangeData(50, 61, 73, false, false));
+  MergeWith(TextChangeData(44, 100, 50, false, false));
   MOZ_ASSERT(mStartOffset == 44,
     "Test 4-4-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 88, // 100 - (73 - 61)
@@ -2495,8 +2501,8 @@ IMENotification::TextChangeDataBase::Test()
    ****************************************************************************/
 
   // Replacing text around start of added text (not sure if actually occurs)
-  MergeWith(TextChangeData(50, 50, 55, false));
-  MergeWith(TextChangeData(48, 52, 49, false));
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(48, 52, 49, false, false));
   MOZ_ASSERT(mStartOffset == 48,
     "Test 5-1-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 50,
@@ -2509,8 +2515,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text around start of replaced text (became shorter) (not sure if
   // actually occurs)
-  MergeWith(TextChangeData(50, 60, 58, false));
-  MergeWith(TextChangeData(43, 50, 48, false));
+  MergeWith(TextChangeData(50, 60, 58, false, false));
+  MergeWith(TextChangeData(43, 50, 48, false, false));
   MOZ_ASSERT(mStartOffset == 43,
     "Test 5-2-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 60,
@@ -2523,8 +2529,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text around start of replaced text (became longer) (not sure if
   // actually occurs)
-  MergeWith(TextChangeData(50, 60, 68, false));
-  MergeWith(TextChangeData(43, 55, 53, false));
+  MergeWith(TextChangeData(50, 60, 68, false, false));
+  MergeWith(TextChangeData(43, 55, 53, false, false));
   MOZ_ASSERT(mStartOffset == 43,
     "Test 5-3-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 60,
@@ -2537,8 +2543,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text around start of replaced text (became shorter) (not sure if
   // actually occurs)
-  MergeWith(TextChangeData(50, 60, 58, false));
-  MergeWith(TextChangeData(43, 50, 128, false));
+  MergeWith(TextChangeData(50, 60, 58, false, false));
+  MergeWith(TextChangeData(43, 50, 128, false, false));
   MOZ_ASSERT(mStartOffset == 43,
     "Test 5-4-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 60,
@@ -2551,8 +2557,8 @@ IMENotification::TextChangeDataBase::Test()
 
   // Replacing text around start of replaced text (became longer) (not sure if
   // actually occurs)
-  MergeWith(TextChangeData(50, 60, 68, false));
-  MergeWith(TextChangeData(43, 55, 65, false));
+  MergeWith(TextChangeData(50, 60, 68, false, false));
+  MergeWith(TextChangeData(43, 55, 65, false, false));
   MOZ_ASSERT(mStartOffset == 43,
     "Test 5-5-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 60,
@@ -2568,8 +2574,8 @@ IMENotification::TextChangeDataBase::Test()
    ****************************************************************************/
 
   // Appending text before already added text (not sure if actually occurs)
-  MergeWith(TextChangeData(30, 30, 45, false));
-  MergeWith(TextChangeData(10, 10, 20, false));
+  MergeWith(TextChangeData(30, 30, 45, false, false));
+  MergeWith(TextChangeData(10, 10, 20, false, false));
   MOZ_ASSERT(mStartOffset == 10,
     "Test 6-1-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 30,
@@ -2581,8 +2587,8 @@ IMENotification::TextChangeDataBase::Test()
   Clear();
 
   // Removing text before already removed text (not sure if actually occurs)
-  MergeWith(TextChangeData(30, 35, 30, false));
-  MergeWith(TextChangeData(10, 25, 10, false));
+  MergeWith(TextChangeData(30, 35, 30, false, false));
+  MergeWith(TextChangeData(10, 25, 10, false, false));
   MOZ_ASSERT(mStartOffset == 10,
     "Test 6-2-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 35,
@@ -2594,8 +2600,8 @@ IMENotification::TextChangeDataBase::Test()
   Clear();
 
   // Replacing text before already replaced text (not sure if actually occurs)
-  MergeWith(TextChangeData(50, 65, 70, false));
-  MergeWith(TextChangeData(13, 24, 15, false));
+  MergeWith(TextChangeData(50, 65, 70, false, false));
+  MergeWith(TextChangeData(13, 24, 15, false, false));
   MOZ_ASSERT(mStartOffset == 13,
     "Test 6-3-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 65,
@@ -2607,8 +2613,8 @@ IMENotification::TextChangeDataBase::Test()
   Clear();
 
   // Replacing text before already replaced text (not sure if actually occurs)
-  MergeWith(TextChangeData(50, 65, 70, false));
-  MergeWith(TextChangeData(13, 24, 36, false));
+  MergeWith(TextChangeData(50, 65, 70, false, false));
+  MergeWith(TextChangeData(13, 24, 36, false, false));
   MOZ_ASSERT(mStartOffset == 13,
     "Test 6-4-1: mStartOffset should be the smallest offset");
   MOZ_ASSERT(mRemovedEndOffset == 65,
diff --git a/widget/nsGUIEventIPC.h b/widget/nsGUIEventIPC.h
index 2a694dbb94b..62b21b27759 100644
--- a/widget/nsGUIEventIPC.h
+++ b/widget/nsGUIEventIPC.h
@@ -735,6 +735,7 @@ struct ParamTraits<mozilla::widget::IMENotification::SelectionChangeDataBase>
     WriteParam(aMsg, aParam.mReversed);
     WriteParam(aMsg, aParam.mCausedByComposition);
     WriteParam(aMsg, aParam.mCausedBySelectionEvent);
+    WriteParam(aMsg, aParam.mOccurredDuringComposition);
   }
 
   static bool Read(const Message* aMsg, void** aIter, paramType* aResult)
@@ -745,7 +746,8 @@ struct ParamTraits<mozilla::widget::IMENotification::SelectionChangeDataBase>
            ReadParam(aMsg, aIter, &aResult->mWritingMode) &&
            ReadParam(aMsg, aIter, &aResult->mReversed) &&
            ReadParam(aMsg, aIter, &aResult->mCausedByComposition) &&
-           ReadParam(aMsg, aIter, &aResult->mCausedBySelectionEvent);
+           ReadParam(aMsg, aIter, &aResult->mCausedBySelectionEvent) &&
+           ReadParam(aMsg, aIter, &aResult->mOccurredDuringComposition);
   }
 };
 
@@ -760,6 +762,7 @@ struct ParamTraits<mozilla::widget::IMENotification::TextChangeDataBase>
     WriteParam(aMsg, aParam.mRemovedEndOffset);
     WriteParam(aMsg, aParam.mAddedEndOffset);
     WriteParam(aMsg, aParam.mCausedByComposition);
+    WriteParam(aMsg, aParam.mOccurredDuringComposition);
   }
 
   static bool Read(const Message* aMsg, void** aIter, paramType* aResult)
@@ -767,7 +770,8 @@ struct ParamTraits<mozilla::widget::IMENotification::TextChangeDataBase>
     return ReadParam(aMsg, aIter, &aResult->mStartOffset) &&
            ReadParam(aMsg, aIter, &aResult->mRemovedEndOffset) &&
            ReadParam(aMsg, aIter, &aResult->mAddedEndOffset) &&
-           ReadParam(aMsg, aIter, &aResult->mCausedByComposition);
+           ReadParam(aMsg, aIter, &aResult->mCausedByComposition) &&
+           ReadParam(aMsg, aIter, &aResult->mOccurredDuringComposition);
   }
 };
 
diff --git a/widget/windows/TSFTextStore.cpp b/widget/windows/TSFTextStore.cpp
index 42c2649463e..c43b81c66b8 100644
--- a/widget/windows/TSFTextStore.cpp
+++ b/widget/windows/TSFTextStore.cpp
@@ -4548,15 +4548,22 @@ TSFTextStore::GetIMEUpdatePreference()
 nsresult
 TSFTextStore::OnTextChangeInternal(const IMENotification& aIMENotification)
 {
+  const IMENotification::TextChangeDataBase& textChangeData =
+    aIMENotification.mTextChangeData;
+
   MOZ_LOG(sTextStoreLog, LogLevel::Debug,
          ("TSF: 0x%p   TSFTextStore::OnTextChangeInternal(aIMENotification={ "
           "mMessage=0x%08X, mTextChangeData={ mStartOffset=%lu, "
-          "mRemovedEndOffset=%lu, mAddedEndOffset=%lu}), mSink=0x%p, "
-          "mSinkMask=%s, mComposition.IsComposing()=%s",
+          "mRemovedEndOffset=%lu, mAddedEndOffset=%lu, "
+          "mCausedByComposition=%s, mOccurredDuringComposition=%s }), "
+          "mSink=0x%p, mSinkMask=%s, mComposition.IsComposing()=%s",
           this, aIMENotification.mMessage,
-          aIMENotification.mTextChangeData.mStartOffset,
-          aIMENotification.mTextChangeData.mRemovedEndOffset,
-          aIMENotification.mTextChangeData.mAddedEndOffset, mSink.get(),
+          textChangeData.mStartOffset,
+          textChangeData.mRemovedEndOffset,
+          textChangeData.mAddedEndOffset,
+          GetBoolName(textChangeData.mCausedByComposition),
+          GetBoolName(textChangeData.mOccurredDuringComposition),
+          mSink.get(),
           GetSinkMaskNameStr(mSinkMask).get(),
           GetBoolName(mComposition.IsComposing())));
 
@@ -4577,12 +4584,9 @@ TSFTextStore::OnTextChangeInternal(const IMENotification& aIMENotification)
 
   if (aIMENotification.mTextChangeData.IsInInt32Range()) {
     TS_TEXTCHANGE textChange;
-    textChange.acpStart =
-      static_cast<LONG>(aIMENotification.mTextChangeData.mStartOffset);
-    textChange.acpOldEnd =
-      static_cast<LONG>(aIMENotification.mTextChangeData.mRemovedEndOffset);
-    textChange.acpNewEnd =
-      static_cast<LONG>(aIMENotification.mTextChangeData.mAddedEndOffset);
+    textChange.acpStart = static_cast<LONG>(textChangeData.mStartOffset);
+    textChange.acpOldEnd = static_cast<LONG>(textChangeData.mRemovedEndOffset);
+    textChange.acpNewEnd = static_cast<LONG>(textChangeData.mAddedEndOffset);
     NotifyTSFOfTextChange(textChange);
   } else {
     MOZ_LOG(sTextStoreLog, LogLevel::Error,
@@ -4635,7 +4639,8 @@ TSFTextStore::OnSelectionChangeInternal(const IMENotification& aIMENotification)
          ("TSF: 0x%p   TSFTextStore::OnSelectionChangeInternal("
           "aIMENotification={ mSelectionChangeData={ mOffset=%lu, "
           "Length()=%lu, mReversed=%s, mWritingMode=%s, "
-          "mCausedByComposition=%s, mCausedBySelectionEvent=%s } }), "
+          "mCausedByComposition=%s, mCausedBySelectionEvent=%s, "
+          "mOccurredDuringComposition=%s } }), "
           "mSink=0x%p, mSinkMask=%s, mIsRecordingActionsWithoutLock=%s, "
           "mComposition.IsComposing()=%s",
           this, selectionChangeData.mOffset, selectionChangeData.Length(),
@@ -4643,12 +4648,32 @@ TSFTextStore::OnSelectionChangeInternal(const IMENotification& aIMENotification)
           GetWritingModeName(selectionChangeData.GetWritingMode()).get(),
           GetBoolName(selectionChangeData.mCausedByComposition),
           GetBoolName(selectionChangeData.mCausedBySelectionEvent),
+          GetBoolName(selectionChangeData.mOccurredDuringComposition),
           mSink.get(), GetSinkMaskNameStr(mSinkMask).get(),
           GetBoolName(mIsRecordingActionsWithoutLock),
           GetBoolName(mComposition.IsComposing())));
 
   mDeferNotifyingTSF = false;
 
+  // A compositionstart event handler can change selection before actually
+  // starting composition in the editor. This causes very complicated issue
+  // because TSF requests to lock the document but we allow to change the
+  // selection for web apps for keeping compatibility.
+  // For now, we should not send selection change notification until the
+  // active composition ends.  However, this causes TSF stores wrong selection
+  // offset.  That might cause TSF stopping working.  So, at next change,
+  // we should cache content *until* composition end.  Then, we will solve
+  // this issue.
+  if (mComposition.IsComposing() &&
+      !selectionChangeData.mOccurredDuringComposition) {
+    MOZ_LOG(sTextStoreLog, LogLevel::Warning,
+           ("TSF: 0x%p   TSFTextStore::OnSelectionChangeInternal(), WARNING, "
+            "ignoring selection change notification which occurred before "
+            "composition start.", this));
+    return NS_OK;
+  }
+
+
   if (IsReadLocked()) {
     // XXX Why don't we mark mPendingOnSelectionChange as true here?
     return NS_OK;
diff --git a/widget/windows/nsAppShell.cpp b/widget/windows/nsAppShell.cpp
index f8794c84466..648a4303614 100644
--- a/widget/windows/nsAppShell.cpp
+++ b/widget/windows/nsAppShell.cpp
@@ -22,17 +22,34 @@
 #include "nsTHashtable.h"
 #include "nsHashKeys.h"
 #include "GeckoProfiler.h"
+#include "nsComponentManagerUtils.h"
+#include "nsITimer.h"
 
 using namespace mozilla;
 using namespace mozilla::widget;
 
+#define WAKE_LOCK_LOG(...) MOZ_LOG(GetWinWakeLockLog(), mozilla::LogLevel::Debug, (__VA_ARGS__))
+PRLogModuleInfo* GetWinWakeLockLog() {
+  static PRLogModuleInfo* log = nullptr;
+  if (!log) {
+    log = PR_NewLogModule("WinWakeLock");
+  }
+  return log;
+}
+
 // A wake lock listener that disables screen saver when requested by
 // Gecko. For example when we're playing video in a foreground tab we
 // don't want the screen saver to turn on.
-class WinWakeLockListener final : public nsIDOMMozWakeLockListener {
+class WinWakeLockListener final : public nsIDOMMozWakeLockListener
+                                , public nsITimerCallback {
 public:
   NS_DECL_ISUPPORTS;
 
+  NS_IMETHODIMP Notify(nsITimer *timer) override {
+    WAKE_LOCK_LOG("WinWakeLock: periodic timer fired");
+    ResetScreenSaverTimeout();
+    return NS_OK;
+  }
 private:
   ~WinWakeLockListener() {}
 
@@ -43,17 +60,79 @@ private:
     // Note the wake lock code ensures that we're not sent duplicate
     // "locked-foreground" notifications when multipe wake locks are held.
     if (aState.EqualsASCII("locked-foreground")) {
-      // Prevent screen saver.
+      WAKE_LOCK_LOG("WinWakeLock: Blocking screen saver");
+      // We block the screen saver by periodically resetting the screen
+      // saver timeout.
+      StartTimer();
+      // Prevent the display turning off. On Win7 and later this also
+      // blocks the screen saver, but we need the timer started above
+      // to block on Win XP and Vista.
       SetThreadExecutionState(ES_DISPLAY_REQUIRED|ES_CONTINUOUS);
     } else {
+      WAKE_LOCK_LOG("WinWakeLock: Unblocking screen saver");
       // Re-enable screen saver.
+      StopTimer();
+      // Unblock display turning off.
       SetThreadExecutionState(ES_CONTINUOUS);
     }
     return NS_OK;
   }
+
+  void StartTimer() {
+    ResetScreenSaverTimeout();
+    MOZ_ASSERT(!mTimer);
+    if (mTimer) {
+      return;
+    }
+
+    nsresult rv;
+    nsCOMPtr<nsITimer> timer = do_CreateInstance(NS_TIMER_CONTRACTID, &rv);
+    if (NS_FAILED(rv)) {
+      NS_WARNING("Failed to create screen saver timeout reset timer");
+      return;
+    }
+    // The minimum screensaver timeout that can be specified with Windows' UI
+    // is 60 seconds. We set a timer to re-jig the screen saver 10 seconds
+    // before we expect the timer to run out, but always at least in 1 second
+    // intervals. We reset the timer at a max of 50 seconds, so that if the
+    // user changes the timeout using the UI, we won't be caught out.
+    int32_t timeout = std::max(std::min(50, (int32_t)mScreenSaverTimeout - 10), 1);
+    uint32_t timeoutMs = (uint32_t)timeout * 1000;
+    WAKE_LOCK_LOG("WinWakeLock: Setting periodic timer for %d ms", timeoutMs);
+    rv = timer->InitWithCallback(this,
+                                 timeoutMs,
+                                 nsITimer::TYPE_REPEATING_SLACK);
+    if (NS_FAILED(rv)) {
+      NS_WARNING("Failed to initialize screen saver timeout reset timer");
+      return;
+    }
+
+    mTimer = timer.forget();
+  }
+
+  void StopTimer() {
+    WAKE_LOCK_LOG("WinWakeLock: StopTimer()");
+    if (!mTimer) {
+      return;
+    }
+    mTimer->Cancel();
+    mTimer = nullptr;
+  }
+
+  // Resets the operating system's timeout for when to disable the screen.
+  // Called periodically to keep the screensaver off.
+  void ResetScreenSaverTimeout() {
+    if (SystemParametersInfo(SPI_GETSCREENSAVETIMEOUT, 0, &mScreenSaverTimeout, 0)) {
+      SystemParametersInfo(SPI_SETSCREENSAVETIMEOUT, mScreenSaverTimeout, NULL, 0);
+    }
+    WAKE_LOCK_LOG("WinWakeLock: ResetScreenSaverTimeout() mScreenSaverTimeout=%d", mScreenSaverTimeout);
+  }
+
+  UINT mScreenSaverTimeout = 60;
+  nsCOMPtr<nsITimer> mTimer;
 };
 
-NS_IMPL_ISUPPORTS(WinWakeLockListener, nsIDOMMozWakeLockListener)
+NS_IMPL_ISUPPORTS(WinWakeLockListener, nsIDOMMozWakeLockListener, nsITimerCallback)
 StaticRefPtr<WinWakeLockListener> sWakeLockListener;
 
 static void
diff --git a/xpfe/appshell/nsContentTreeOwner.cpp b/xpfe/appshell/nsContentTreeOwner.cpp
index 772e34636f8..c86b5330117 100644
--- a/xpfe/appshell/nsContentTreeOwner.cpp
+++ b/xpfe/appshell/nsContentTreeOwner.cpp
@@ -1136,7 +1136,7 @@ nsSiteWindow::Blur(void)
       return NS_OK;
     }
 
-    nsCOMPtr<nsIDOMWindow> domWindow(docshell->GetWindow());
+    nsCOMPtr<nsPIDOMWindow> domWindow = do_QueryInterface(docshell->GetWindow());
     if (domWindow)
       domWindow->Focus();
   }
diff --git a/xpfe/appshell/nsXULWindow.cpp b/xpfe/appshell/nsXULWindow.cpp
index 3274b893272..1b239c60a4c 100644
--- a/xpfe/appshell/nsXULWindow.cpp
+++ b/xpfe/appshell/nsXULWindow.cpp
@@ -1025,9 +1025,12 @@ void nsXULWindow::OnChromeLoaded()
         nsCOMPtr<nsIDocShellTreeOwner> treeOwner;
         docShellAsItem->GetTreeOwner(getter_AddRefs(treeOwner));
         if (treeOwner) {
-          int32_t width, height;
-          cv->GetContentSize(&width, &height);
-          treeOwner->SizeShellTo(docShellAsItem, width, height);
+          // GetContentSize can fail, so initialise |width| and |height| to be
+          // on the safe side.
+          int32_t width = 0, height = 0;
+          if (NS_SUCCEEDED(cv->GetContentSize(&width, &height))) {
+            treeOwner->SizeShellTo(docShellAsItem, width, height);
+          }
         }
       }
     }
@@ -1179,9 +1182,8 @@ bool nsXULWindow::LoadSizeFromXUL()
     // constrain to screen size
     nsCOMPtr<nsIDOMWindow> domWindow;
     GetWindowDOMWindow(getter_AddRefs(domWindow));
-    if (domWindow) {
-      nsCOMPtr<nsIDOMScreen> screen;
-      domWindow->GetScreen(getter_AddRefs(screen));
+    if (nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(domWindow)) {
+      nsCOMPtr<nsIDOMScreen> screen = window->GetScreen();
       if (screen) {
         int32_t screenWidth;
         int32_t screenHeight;
@@ -1265,7 +1267,8 @@ bool nsXULWindow::LoadMiscPersistentAttributesFromXUL()
   if (sizeMode == nsSizeMode_Fullscreen) {
     nsCOMPtr<nsIDOMWindow> ourWindow;
     GetWindowDOMWindow(getter_AddRefs(ourWindow));
-    ourWindow->SetFullScreen(true);
+    nsCOMPtr<nsPIDOMWindow> piWindow = do_QueryInterface(ourWindow);
+    piWindow->SetFullScreen(true);
   } else {
     mWindow->SetSizeMode(sizeMode);
   }
@@ -1480,7 +1483,7 @@ NS_IMETHODIMP nsXULWindow::SavePersistentAttributes()
 
   bool isFullscreen = false;
   if (nsPIDOMWindow* domWindow = mDocShell->GetWindow()) {
-    domWindow->GetFullScreen(&isFullscreen);
+    isFullscreen = domWindow->GetFullScreen();
   }
 
   // get our size, position and mode to persist