diff --git a/content/base/src/nsFrameLoader.cpp b/content/base/src/nsFrameLoader.cpp
index 6c2b08e3f8f..8bba8a6177d 100644
--- a/content/base/src/nsFrameLoader.cpp
+++ b/content/base/src/nsFrameLoader.cpp
@@ -444,15 +444,10 @@ nsFrameLoader::ReallyStartLoadingInternal()
   mDocShell->CreateLoadInfo(getter_AddRefs(loadInfo));
   NS_ENSURE_TRUE(loadInfo, NS_ERROR_FAILURE);
 
-  if (!OwnerIsBrowserFrame()) {
-    // We'll use our principal, not that of the document loaded inside us.
-    // This is very important; needed to prevent XSS attacks on documents
-    // loaded in subframes!
-    //
-    // (For <iframe mozbrowser>, don't set an owner; it's as though the iframe
-    // is a top-level window.)
-    loadInfo->SetOwner(mOwnerContent->NodePrincipal());
-  }
+  // We'll use our principal, not that of the document loaded inside us.  This
+  // is very important; needed to prevent XSS attacks on documents loaded in
+  // subframes!
+  loadInfo->SetOwner(mOwnerContent->NodePrincipal());
 
   nsCOMPtr<nsIURI> referrer;
   rv = mOwnerContent->NodePrincipal()->GetURI(getter_AddRefs(referrer));
diff --git a/docshell/base/nsDocShell.cpp b/docshell/base/nsDocShell.cpp
index 929e13bf9ef..4d318a9e4d2 100644
--- a/docshell/base/nsDocShell.cpp
+++ b/docshell/base/nsDocShell.cpp
@@ -8810,9 +8810,7 @@ nsDocShell::GetInheritedPrincipal(bool aConsiderCurrentDocument)
         inheritedFromCurrent = true;
     }
 
-    // Browser frames don't inherit their principal from their parent.  This
-    // makes them more like top-level windows.
-    if (!document && !mIsBrowserFrame) {
+    if (!document) {
         nsCOMPtr<nsIDocShellTreeItem> parentItem;
         GetSameTypeParent(getter_AddRefs(parentItem));
         if (parentItem) {
diff --git a/dom/browser-element/mochitest/Makefile.in b/dom/browser-element/mochitest/Makefile.in
index 831a77914e4..855fd8030e4 100644
--- a/dom/browser-element/mochitest/Makefile.in
+++ b/dom/browser-element/mochitest/Makefile.in
@@ -48,9 +48,6 @@ _TEST_FILES = \
 		test_browserElement_inproc_PromptConfirm.html \
 		browserElement_Close.js \
 		test_browserElement_inproc_Close.html \
-		browserElement_CloseFromOpener.js \
-		test_browserElement_inproc_CloseFromOpener.html \
-		file_browserElement_CloseFromOpener.html \
 		browserElement_OpenWindow.js \
 		test_browserElement_inproc_OpenWindow.html \
 		file_browserElement_Open1.html \
@@ -62,8 +59,6 @@ _TEST_FILES = \
 		test_browserElement_inproc_SecurityChange.html \
 		file_browserElement_SecurityChange.html \
 		browserElement_BackForward.js \
-		browserElement_Principal.js \
-		test_browserElement_inproc_Principal.html \
 		$(NULL)
 
 # OOP tests don't work on Windows (bug 763081).
@@ -83,12 +78,10 @@ _TEST_FILES += \
 		test_browserElement_oop_PromptCheck.html \
 		test_browserElement_oop_PromptConfirm.html \
 		test_browserElement_oop_Close.html \
-		test_browserElement_oop_CloseFromOpener.html \
 		test_browserElement_oop_OpenWindow.html \
 		test_browserElement_oop_OpenWindowRejected.html \
 		test_browserElement_oop_SecurityChange.html \
 		test_browserElement_oop_BackForward.html \
-		test_browserElement_oop_Principal.html \
 		$(NULL)
 endif
 
diff --git a/dom/browser-element/mochitest/browserElement_CloseFromOpener.js b/dom/browser-element/mochitest/browserElement_CloseFromOpener.js
deleted file mode 100644
index 46f26578333..00000000000
--- a/dom/browser-element/mochitest/browserElement_CloseFromOpener.js
+++ /dev/null
@@ -1,34 +0,0 @@
-/* Any copyright is dedicated to the public domain.
-   http://creativecommons.org/publicdomain/zero/1.0/ */
-
-// Bug 764718 - Test that window.close() works from the opener window.
-"use strict";
-
-SimpleTest.waitForExplicitFinish();
-
-function runTest() {
-  browserElementTestHelpers.setEnabledPref(true);
-  browserElementTestHelpers.addToWhitelist();
-
-  var iframe = document.createElement('iframe');
-  iframe.mozbrowser = true;
-
-  iframe.addEventListener('mozbrowseropenwindow', function(e) {
-    ok(true, "got openwindow event.");
-    document.body.appendChild(e.detail.frameElement);
-
-    e.detail.frameElement.addEventListener("mozbrowserclose", function(e) {
-      ok(true, "got mozbrowserclose event.");
-      SimpleTest.finish();
-    });
-  });
-
-
-  document.body.appendChild(iframe);
-
-  // file_browserElement_CloseFromOpener opens a new window and then calls
-  // close() on it.
-  iframe.src = "file_browserElement_CloseFromOpener.html";
-}
-
-runTest();
diff --git a/dom/browser-element/mochitest/browserElement_Principal.js b/dom/browser-element/mochitest/browserElement_Principal.js
deleted file mode 100644
index f238d427280..00000000000
--- a/dom/browser-element/mochitest/browserElement_Principal.js
+++ /dev/null
@@ -1,44 +0,0 @@
-/* Any copyright is dedicated to the public domain.
-   http://creativecommons.org/publicdomain/zero/1.0/ */
-
-// Bug 764718 - Test that <iframe mozbrowser>'s have a different principal than
-// their creator.
-"use strict";
-
-function runTest() {
-  browserElementTestHelpers.setEnabledPref(true);
-  browserElementTestHelpers.addToWhitelist();
-
-  var iframe = document.createElement('iframe');
-  iframe.mozbrowser = true;
-  document.body.appendChild(iframe);
-
-  if (!iframe.contentWindow) {
-    ok(true, "OOP, can't access contentWindow.");
-    return;
-  }
-
-  SimpleTest.waitForExplicitFinish();
-
-  // Try reading iframe.contentWindow.location now, and then from a timeout.
-  // They both should throw exceptions.
-  checkCantReadLocation(iframe);
-  SimpleTest.executeSoon(function() {
-    checkCantReadLocation(iframe);
-    SimpleTest.finish();
-  });
-}
-
-function checkCantReadLocation(iframe) {
-  try {
-    if (iframe.contentWindow.location == 'foo') {
-      ok(false, 'not reached');
-    }
-    ok(false, 'should have gotten exception');
-  }
-  catch(e) {
-    ok(true, 'got exception reading contentWindow.location');
-  }
-}
-
-runTest();
diff --git a/dom/browser-element/mochitest/file_browserElement_CloseFromOpener.html b/dom/browser-element/mochitest/file_browserElement_CloseFromOpener.html
deleted file mode 100644
index 4a08c2792b6..00000000000
--- a/dom/browser-element/mochitest/file_browserElement_CloseFromOpener.html
+++ /dev/null
@@ -1,8 +0,0 @@
-<html>
-<body>
-<script>
-var win = window.open('file_empty.html');
-win.close();
-</script>
-</body>
-</html>
diff --git a/dom/browser-element/mochitest/test_browserElement_inproc_CloseFromOpener.html b/dom/browser-element/mochitest/test_browserElement_inproc_CloseFromOpener.html
deleted file mode 100644
index 3c7ee4d874b..00000000000
--- a/dom/browser-element/mochitest/test_browserElement_inproc_CloseFromOpener.html
+++ /dev/null
@@ -1,18 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=757182
--->
-<head>
-  <title>Test for Bug 757182</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script type="application/javascript" src="browserElementTestHelpers.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=757182">Mozilla Bug 757182</a>
-
-<script type="application/javascript;version=1.7" src="browserElement_CloseFromOpener.js">
-</script>
-</body>
-</html>
diff --git a/dom/browser-element/mochitest/test_browserElement_inproc_Principal.html b/dom/browser-element/mochitest/test_browserElement_inproc_Principal.html
deleted file mode 100644
index 10e1a856f7b..00000000000
--- a/dom/browser-element/mochitest/test_browserElement_inproc_Principal.html
+++ /dev/null
@@ -1,18 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=757182
--->
-<head>
-  <title>Test for Bug 757182</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script type="application/javascript" src="browserElementTestHelpers.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=757182">Mozilla Bug 757182</a>
-
-<script type="application/javascript;version=1.7" src="browserElement_Principal.js">
-</script>
-</body>
-</html>
diff --git a/dom/browser-element/mochitest/test_browserElement_oop_CloseFromOpener.html b/dom/browser-element/mochitest/test_browserElement_oop_CloseFromOpener.html
deleted file mode 100644
index 3c7ee4d874b..00000000000
--- a/dom/browser-element/mochitest/test_browserElement_oop_CloseFromOpener.html
+++ /dev/null
@@ -1,18 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=757182
--->
-<head>
-  <title>Test for Bug 757182</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script type="application/javascript" src="browserElementTestHelpers.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=757182">Mozilla Bug 757182</a>
-
-<script type="application/javascript;version=1.7" src="browserElement_CloseFromOpener.js">
-</script>
-</body>
-</html>
diff --git a/dom/browser-element/mochitest/test_browserElement_oop_Principal.html b/dom/browser-element/mochitest/test_browserElement_oop_Principal.html
deleted file mode 100644
index 10e1a856f7b..00000000000
--- a/dom/browser-element/mochitest/test_browserElement_oop_Principal.html
+++ /dev/null
@@ -1,18 +0,0 @@
-<!DOCTYPE HTML>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=757182
--->
-<head>
-  <title>Test for Bug 757182</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <script type="application/javascript" src="browserElementTestHelpers.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=757182">Mozilla Bug 757182</a>
-
-<script type="application/javascript;version=1.7" src="browserElement_Principal.js">
-</script>
-</body>
-</html>
diff --git a/xpfe/appshell/src/nsContentTreeOwner.cpp b/xpfe/appshell/src/nsContentTreeOwner.cpp
index b61e04693f8..d1c0e074660 100644
--- a/xpfe/appshell/src/nsContentTreeOwner.cpp
+++ b/xpfe/appshell/src/nsContentTreeOwner.cpp
@@ -851,14 +851,14 @@ nsContentTreeOwner::ProvideWindow(nsIDOMWindow* aParent,
       !(aChromeFlags & (nsIWebBrowserChrome::CHROME_MODAL |
                         nsIWebBrowserChrome::CHROME_OPENAS_DIALOG |
                         nsIWebBrowserChrome::CHROME_OPENAS_CHROME))) {
-    *aWindowIsNew =
+    bool openSucceeded =
       BrowserElementParent::OpenWindowInProcess(aParent, aURI, aName,
                                                 aFeatures, aReturn);
 
     // If OpenWindowInProcess failed (perhaps because the embedder blocked the
     // popup), tell our caller not to proceed trying to create a new window
     // through other means.
-    return *aWindowIsNew ? NS_OK : NS_ERROR_ABORT;
+    return openSucceeded ? NS_OK : NS_ERROR_ABORT;
   }
 
   // Where should we open this?