diff --git a/browser/locales/en-US/chrome/browser/browser.properties b/browser/locales/en-US/chrome/browser/browser.properties
index 7f58fe4f6ec..5a0c9acb943 100644
--- a/browser/locales/en-US/chrome/browser/browser.properties
+++ b/browser/locales/en-US/chrome/browser/browser.properties
@@ -357,7 +357,6 @@ webapps.install = Install
 webapps.install.accesskey = I
 #LOCALIZATION NOTE (webapps.requestInstall) %1$S is the web app name, %2$S is the site from which the web app is installed
 webapps.requestInstall = Do you want to install "%1$S" from this site (%2$S)?
-webapps.install.success = Application Installed
 
 # Telemetry opt-out prompt for Aurora and Nightly
 # LOCALIZATION NOTE (telemetryOptOutPrompt): %1$S and %3$S will be replaced by
diff --git a/browser/modules/webappsUI.jsm b/browser/modules/webappsUI.jsm
index e24ef83dbe7..052da45b3d8 100644
--- a/browser/modules/webappsUI.jsm
+++ b/browser/modules/webappsUI.jsm
@@ -29,12 +29,10 @@ let webappsUI = {
 
     switch(aTopic) {
       case "webapps-ask-install":
-        let win = this._getWindowForId(data.oid);
-        if (win && win.location.href == data.from) {
-          this.doInstall(data, win);
-        }
+        let [chromeWin, browser] = this._getBrowserForId(data.oid);
+        if (chromeWin)
+          this.doInstall(data, browser, chromeWin);
         break;
-
       case "webapps-launch":
         DOMApplicationRegistry.getManifestFor(data.origin, (function(aManifest) {
           if (!aManifest)
@@ -85,14 +83,27 @@ let webappsUI = {
     }
   },
 
-  doInstall: function(aData, aWindow) {
-    let browser = aWindow.QueryInterface(Ci.nsIInterfaceRequestor)
-                         .getInterface(Ci.nsIWebNavigation)
-                         .QueryInterface(Ci.nsIDocShell)
-                         .chromeEventHandler;
+  _getBrowserForId: function(aId) {
+    let someWindow = Services.wm.getMostRecentWindow(null);
 
-    let chromeWin = browser.ownerDocument.defaultView;
-    let bundle = chromeWin.gNavigatorBundle;
+    if (someWindow) {
+      let windowUtils = someWindow.QueryInterface(Ci.nsIInterfaceRequestor)
+                                  .getInterface(Ci.nsIDOMWindowUtils);
+      let content = windowUtils.getOuterWindowWithId(aId);
+      if (content) {
+        let browser = content.QueryInterface(Ci.nsIInterfaceRequestor)
+                      .getInterface(Ci.nsIWebNavigation)
+                      .QueryInterface(Ci.nsIDocShell).chromeEventHandler;
+        let win = browser.ownerDocument.defaultView;
+        return [win, browser];
+      }
+    }
+
+    return [null, null];
+  },
+
+  doInstall: function(aData, aBrowser, aWindow) {
+    let bundle = aWindow.gNavigatorBundle;
 
     let mainAction = {
       label: bundle.getString("webapps.install"),
@@ -106,14 +117,13 @@ let webappsUI = {
           }
 
           DOMApplicationRegistry.confirmInstall(aData, false, localDir);
-          installationSuccessNotification(app, chromeWin);
         } else {
           DOMApplicationRegistry.denyInstall(aData);
         }
       }
     };
 
-    let requestingURI = chromeWin.makeURI(aData.from);
+    let requestingURI = aWindow.makeURI(aData.from);
     let manifest = new DOMApplicationManifest(aData.app.manifest, aData.app.origin);
 
     let host;
@@ -124,35 +134,10 @@ let webappsUI = {
     }
 
     let message = bundle.getFormattedString("webapps.requestInstall",
-                                            [manifest.name, host]);
+                                            [manifest.name, host], 2);
 
-    chromeWin.PopupNotifications.show(browser, "webapps-install", message,
-                                      "webapps-notification-icon", mainAction);
-  },
+    aWindow.PopupNotifications.show(aBrowser, "webapps-install", message,
+                                    "webapps-notification-icon", mainAction);
 
-  _getWindowForId: function(aId) {
-     let someWindow = Services.wm.getMostRecentWindow(null);
-     return someWindow &&
-            someWindow.QueryInterface(Ci.nsIInterfaceRequestor)
-                      .getInterface(Ci.nsIDOMWindowUtils)
-                      .getOuterWindowWithId(aId);
-  }
-}
-
-function installationSuccessNotification(app, aWindow) {
-  let bundle = aWindow.gNavigatorBundle;
-
-  if (("@mozilla.org/alerts-service;1" in Cc)) {
-    let notifier;
-    try {
-      notifier = Cc["@mozilla.org/alerts-service;1"].
-                 getService(Ci.nsIAlertsService);
-
-      notifier.showAlertNotification(app.iconURI.spec,
-                                    bundle.getString("webapps.install.success"),
-                                    app.appNameAsFilename,
-                                    false, null, null);
-
-    } catch (ex) {}
   }
 }
diff --git a/dom/apps/src/Webapps.jsm b/dom/apps/src/Webapps.jsm
index 1ea0011d02b..87c5d551ee1 100644
--- a/dom/apps/src/Webapps.jsm
+++ b/dom/apps/src/Webapps.jsm
@@ -14,7 +14,6 @@ let EXPORTED_SYMBOLS = ["DOMApplicationRegistry", "DOMApplicationManifest"];
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
 Cu.import("resource://gre/modules/FileUtils.jsm");
-Cu.import("resource://gre/modules/WebappOSUtils.jsm");
 
 const WEBAPP_RUNTIME = Services.appinfo.ID == "webapprt@mozilla.org";
 
@@ -172,7 +171,7 @@ let DOMApplicationRegistry = {
         this.uninstall(msg);
         break;
       case "Webapps:Launch":
-        WebappOSUtils.launch(msg);
+        Services.obs.notifyObservers(this, "webapps-launch", JSON.stringify(msg));
         break;
       case "Webapps:GetInstalled":
         this.getInstalled(msg);
diff --git a/dom/tests/mochitest/webapps/Makefile.in b/dom/tests/mochitest/webapps/Makefile.in
index d5679ad6163..d2e7e887580 100644
--- a/dom/tests/mochitest/webapps/Makefile.in
+++ b/dom/tests/mochitest/webapps/Makefile.in
@@ -16,7 +16,6 @@ DIRS = \
 
 MOCHITEST_CHROME_FILES	= \
     test_bug_765063.xul \
-    test_bug_771294.xul \
     test_install_app.xul \
     test_list_api.xul \
     test_install_errors.xul \
diff --git a/dom/tests/mochitest/webapps/apps/Makefile.in b/dom/tests/mochitest/webapps/apps/Makefile.in
index e297ba2d478..53f4500dba4 100644
--- a/dom/tests/mochitest/webapps/apps/Makefile.in
+++ b/dom/tests/mochitest/webapps/apps/Makefile.in
@@ -12,7 +12,6 @@ include $(DEPTH)/config/autoconf.mk
 
 MOCHITEST_CHROME_FILES	= \
     bug_765063.xul \
-    bug_771294.xul \
     include.html \
     wild_crazy.webapp \
     wild_crazy.webapp^headers^ \
diff --git a/dom/tests/mochitest/webapps/apps/bug_765063.xul b/dom/tests/mochitest/webapps/apps/bug_765063.xul
index 462f06870cf..8f8d1c01f66 100644
--- a/dom/tests/mochitest/webapps/apps/bug_765063.xul
+++ b/dom/tests/mochitest/webapps/apps/bug_765063.xul
@@ -6,6 +6,6 @@
 <window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
   <script>
     navigator.mozApps.install("http://www.example.com:80/chrome/dom/tests/mochitest/webapps/apps/super_crazy.webapp", null);
-    history.pushState({}, "", "modified-url");
+    document.location = "about:blank";
   </script>
 </window>
diff --git a/dom/tests/mochitest/webapps/apps/bug_771294.xul b/dom/tests/mochitest/webapps/apps/bug_771294.xul
deleted file mode 100644
index 66d1d6f7a28..00000000000
--- a/dom/tests/mochitest/webapps/apps/bug_771294.xul
+++ /dev/null
@@ -1,11 +0,0 @@
-<?xml version="1.0"?>
-
-<!-- Any copyright is dedicated to the Public Domain.
-   - http://creativecommons.org/publicdomain/zero/1.0/ -->
-
-<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
-  <script>
-    navigator.mozApps.install("http://www.example.com:80/chrome/dom/tests/mochitest/webapps/apps/super_crazy.webapp", null);
-    window.location = "about:blank";
-  </script>
-</window>
diff --git a/dom/tests/mochitest/webapps/test_bug_765063.xul b/dom/tests/mochitest/webapps/test_bug_765063.xul
index 21f503e68f3..5ac9a6d6647 100644
--- a/dom/tests/mochitest/webapps/test_bug_765063.xul
+++ b/dom/tests/mochitest/webapps/test_bug_765063.xul
@@ -18,22 +18,19 @@
 <script> 
 SimpleTest.waitForExplicitFinish();
 
-var mmListener = {
-  receiveMessage: function(aMessage) {
-    ppmm.removeMessageListener("Webapps:Install", mmListener);
-
-    var msg = aMessage.json;
-    is(msg.from.indexOf("modified-url"), -1, "the install origin didn't change");
-
+// Observe app installation and confirm that the install origin didn't change.
+var observer = {
+  observe: function observe(subject, topic, data) {
+    Services.obs.removeObserver(observer, "webapps-sync-install");
+    ok(JSON.parse(data).installOrigin == "http://www.example.com",
+       "the install origin didn't change");
     tearDown();
     SimpleTest.finish();
   }
 };
 
-var ppmm = Components.classes["@mozilla.org/parentprocessmessagemanager;1"]
-                     .getService(Components.interfaces.nsIFrameMessageManager);
-
-ppmm.addMessageListener("Webapps:Install", mmListener);
+Components.utils.import("resource://gre/modules/Services.jsm");
+Services.obs.addObserver(observer, "webapps-sync-install", false);
 </script> 
 
   <!-- Load a page that initiates an app installation and then immediately
diff --git a/dom/tests/mochitest/webapps/test_bug_771294.xul b/dom/tests/mochitest/webapps/test_bug_771294.xul
deleted file mode 100644
index 77dc508697a..00000000000
--- a/dom/tests/mochitest/webapps/test_bug_771294.xul
+++ /dev/null
@@ -1,53 +0,0 @@
-<?xml version="1.0"?>
-
-<!-- Any copyright is dedicated to the Public Domain.
-   - http://creativecommons.org/publicdomain/zero/1.0/ -->
-
-<?xml-stylesheet type="text/css" href="chrome://global/skin"?>
-<?xml-stylesheet type="text/css" href="chrome://mochikit/content/tests/SimpleTest/test.css"?>
-
-<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
-        title="Mozilla Bug 771294">
-  <script type="application/javascript" src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js"/>
-  <script type="application/javascript" src="apphelper.js"/>
-  <script type="application/javascript" src="jshelper.js"/>
-
-<script>
-SimpleTest.waitForExplicitFinish();
-
-Components.utils.import('resource://gre/modules/Services.jsm');
-
-var blocked = true;
-
-Services.obs.addObserver(
-  function observeShowing() {
-    Services.obs.removeObserver(observeShowing, "PopupNotifications-showing");
-    blocked = false;
-  },
-  "PopupNotifications-showing",
-  false
-);
-
-Services.obs.addObserver(
-  function observeInstalling() {
-    Services.obs.removeObserver(observeInstalling, "webapps-ask-install");
-    // Spin the event loop before running the test to give the registry time
-    // to process the install request and (hopefully not) show the doorhanger.
-    setTimeout(function verify() {
-      ok(blocked, "Install panel was blocked after immediate redirect");
-      tearDown();
-      SimpleTest.finish();
-    }, 0);
-  },
-  "webapps-ask-install",
-  false
-);
-
-</script>
-
-  <!-- Load a page that initiates an app installation and then immediately
-     - redirects to a page at a different origin.  We can't do this directly
-     - inside this test page, because that would cause the test to hang. -->
-  <iframe src="http://www.example.com:80/chrome/dom/tests/mochitest/webapps/apps/bug_771294.xul"/>
-
-</window>
diff --git a/toolkit/Makefile.in b/toolkit/Makefile.in
index 29748c67d78..b30fb4c627e 100644
--- a/toolkit/Makefile.in
+++ b/toolkit/Makefile.in
@@ -24,7 +24,6 @@ PARALLEL_DIRS = \
   obsolete \
   profile \
   themes \
-  webapps \
   $(NULL)
 
 DIRS += \
diff --git a/toolkit/content/PopupNotifications.jsm b/toolkit/content/PopupNotifications.jsm
index d374f4b3980..f6e6d760c63 100644
--- a/toolkit/content/PopupNotifications.jsm
+++ b/toolkit/content/PopupNotifications.jsm
@@ -241,9 +241,6 @@ PopupNotifications.prototype = {
     let notifications = this._getNotificationsForBrowser(browser);
     notifications.push(notification);
 
-    // Notify observers that we're showing the popup (useful for testing)
-    this._notify("showing");
-
     let fm = Cc["@mozilla.org/focus-manager;1"].getService(Ci.nsIFocusManager);
     if (browser == this.tabbrowser.selectedBrowser && fm.activeWindow == this.window) {
       // show panel now
diff --git a/toolkit/themes/gnomestripe/global/alerts/alert.css b/toolkit/themes/gnomestripe/global/alerts/alert.css
index 072923dbd29..69b6412b58c 100644
--- a/toolkit/themes/gnomestripe/global/alerts/alert.css
+++ b/toolkit/themes/gnomestripe/global/alerts/alert.css
@@ -27,11 +27,6 @@
   min-width: 46px;
 }
 
-#alertImage {
-  max-width: 48px;
-  max-height: 48px;
-}
-
 .alertTitle {
   font-weight: bold;
 }
diff --git a/toolkit/themes/winstripe/global/alerts/alert.css b/toolkit/themes/winstripe/global/alerts/alert.css
index 1d70096e0c2..688a6f0c1f4 100644
--- a/toolkit/themes/winstripe/global/alerts/alert.css
+++ b/toolkit/themes/winstripe/global/alerts/alert.css
@@ -32,11 +32,6 @@
   font-weight: bold;
 }
 
-#alertImage {
-  max-width: 48px;
-  max-height: 48px;
-}
-
 .alertText {
   -moz-margin-end: 6px;
 }
diff --git a/toolkit/webapps/Makefile.in b/toolkit/webapps/Makefile.in
deleted file mode 100644
index 8ea5cafd989..00000000000
--- a/toolkit/webapps/Makefile.in
+++ /dev/null
@@ -1,18 +0,0 @@
-# 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/.
-
-DEPTH     = ../..
-topsrcdir = @top_srcdir@
-srcdir    = @srcdir@
-VPATH     = @srcdir@
-
-include $(DEPTH)/config/autoconf.mk
-
-include $(topsrcdir)/config/config.mk
-
-EXTRA_PP_JS_MODULES = \
-	WebappOSUtils.jsm \
-	$(NULL)
-
-include $(topsrcdir)/config/rules.mk
diff --git a/toolkit/webapps/WebappOSUtils.jsm b/toolkit/webapps/WebappOSUtils.jsm
deleted file mode 100644
index c2b4941dd4a..00000000000
--- a/toolkit/webapps/WebappOSUtils.jsm
+++ /dev/null
@@ -1,81 +0,0 @@
-/* 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/. */
-
-const Cc = Components.classes;
-const Ci = Components.interfaces;
-const CC = Components.Constructor;
-
-let EXPORTED_SYMBOLS = ["WebappOSUtils"];
-
-let WebappOSUtils = {
-  launch: function(aData) {
-#ifdef XP_WIN
-    let appRegKey;
-    try {
-      let open = CC("@mozilla.org/windows-registry-key;1",
-                    "nsIWindowsRegKey", "open");
-      let initWithPath = CC("@mozilla.org/file/local;1",
-                            "nsILocalFile", "initWithPath");
-      let initProcess = CC("@mozilla.org/process/util;1",
-                           "nsIProcess", "init");
-
-      appRegKey = open(Ci.nsIWindowsRegKey.ROOT_KEY_CURRENT_USER,
-                       "SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\",
-                       aData.origin, Ci.nsIWindowsRegKey.ACCESS_READ);
-
-      let launchTarget = initWithPath(appRegKey.readStringValue("InstallLocation"));
-      launchTarget.append(appRegKey.readStringValue("AppFilename") + ".exe");
-
-      let process = initProcess(launchTarget);
-      process.runwAsync([], 0);
-    } catch (e) {
-      return false;
-    } finally {
-      if (appRegKey) {
-        appRegKey.close();
-      }
-    }
-
-    return true;
-#elifdef XP_MACOSX
-    let mwaUtils = Cc["@mozilla.org/widget/mac-web-app-utils;1"]
-                    .createInstance(Ci.nsIMacWebAppUtils);
-    let appPath;
-    try {
-      appPath = mwaUtils.pathForAppWithIdentifier(aData.origin);
-    } catch (e) {}
-
-    if (appPath) {
-      mwaUtils.launchAppWithIdentifier(aData.origin);
-      return true;
-    }
-
-    return false;
-#elifdef XP_UNIX
-    let origin = Services.io.newURI(aData.origin, null, null);
-    let installDir = "." + origin.scheme + ";" + origin.host;
-    if (origin.port != -1)
-      installDir += ";" + origin.port;
-
-    let exeFile = Services.dirsvc.get("Home", Ci.nsIFile);
-    exeFile.append(installDir);
-    exeFile.append("webapprt-stub");
-
-    try {
-      if (exeFile.exists()) {
-        let process = Cc["@mozilla.org/process/util;1"]
-                        .createInstance(Ci.nsIProcess);
-        process.init(exeFile);
-        process.runAsync([], 0);
-        return true;
-      }
-    } catch (e) {}
-
-    return false;
-#else
-    Services.obs.notifyObservers(this, "webapps-launch", JSON.stringify(aData));
-    return true;
-#endif
-  }
-}
diff --git a/widget/cocoa/nsMacWebAppUtils.mm b/widget/cocoa/nsMacWebAppUtils.mm
index 09f21adfdbc..08d4655d1d3 100644
--- a/widget/cocoa/nsMacWebAppUtils.mm
+++ b/widget/cocoa/nsMacWebAppUtils.mm
@@ -37,22 +37,3 @@ NS_IMETHODIMP nsMacWebAppUtils::PathForAppWithIdentifier(const nsAString& bundle
 
   NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
 }
-
-NS_IMETHODIMP nsMacWebAppUtils::LaunchAppWithIdentifier(const nsAString& bundleIdentifier) {
-  NS_OBJC_BEGIN_TRY_ABORT_BLOCK_NSRESULT;
-
-  NSAutoreleasePool* ap = [[NSAutoreleasePool alloc] init];
-
-  // Note this might return false, meaning the app wasnt launched for some reason. 
-  BOOL success = [[NSWorkspace sharedWorkspace] launchAppWithBundleIdentifier:
-                        [NSString stringWithCharacters:((nsString)bundleIdentifier).get() length:((nsString)bundleIdentifier).Length()]
-                        options: nil
-                        additionalEventParamDescriptor: nil
-                        launchIdentifier: NULL];
-
-
-  [ap release];
-  return NS_OK;
-
-  NS_OBJC_END_TRY_ABORT_BLOCK_NSRESULT;
-}
diff --git a/widget/nsIMacWebAppUtils.idl b/widget/nsIMacWebAppUtils.idl
index 12a42ea17c1..1e47d09b901 100644
--- a/widget/nsIMacWebAppUtils.idl
+++ b/widget/nsIMacWebAppUtils.idl
@@ -17,9 +17,4 @@ interface nsIMacWebAppUtils : nsISupports {
    */
   AString pathForAppWithIdentifier(in AString bundleIdentifier);
 
-  /**
-   * Launch the app with the given identifier, if it exists.
-   */
-  void launchAppWithIdentifier(in AString bundleIdentifier);
-
 };