--- a/browser/components/Makefile.in
+++ b/browser/components/Makefile.in
@@ -80,15 +80,19 @@ ifndef WINCE
 PARALLEL_DIRS += wintaskbar
 endif
 endif
 
 ifdef MOZ_SAFE_BROWSING
 PARALLEL_DIRS += safebrowsing
 endif
 
+ifdef ENABLE_TESTS
+DIRS += test
+endif
+
 DIRS += build
 
 ifdef MOZILLA_OFFICIAL
 DEFINES += -DOFFICIAL_BUILD=1
 endif
 
 include $(topsrcdir)/config/rules.mk

--- a/browser/components/nsBrowserContentHandler.js
+++ b/browser/components/nsBrowserContentHandler.js
@@ -15,16 +15,17 @@
 #
 # The Initial Developer of the Original Code is
 # Benjamin Smedberg <benjamin@smedbergs.us>
 #
 # Portions created by the Initial Developer are Copyright (C) 2004
 # the Initial Developer. All Rights Reserved.
 #
 # Contributor(s):
+#   Robert Strong <robert.bugzilla@gmail.com>
 #
 # Alternatively, the contents of this file may be used under the terms of
 # either the GNU General Public License Version 2 or later (the "GPL"), or
 # the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 # in which case the provisions of the GPL or the LGPL are applicable instead
 # of those above. If you wish to allow use of your version of this file only
 # under the terms of either the GPL or the LGPL, and not to allow others to
 # use your version of this file under the terms of the MPL, indicate your
@@ -144,16 +145,50 @@ function needHomepageOverride(prefb) {
     
     prefb.setCharPref("browser.startup.homepage_override.mstone", mstone);
     return (savedmstone ? OVERRIDE_NEW_MSTONE : OVERRIDE_NEW_PROFILE);
   }
 
   return OVERRIDE_NONE;
 }
 
+/**
+ * Gets the override page for the first run after the application has been
+ * updated.
+ * @param  defaultOverridePage
+ *         The default override page.
+ * @return The override page.
+ */
+function getPostUpdateOverridePage(defaultOverridePage) {
+  var um = Components.classes["@mozilla.org/updates/update-manager;1"]
+                     .getService(Components.interfaces.nsIUpdateManager);
+  try {
+    // If the updates.xml file is deleted then getUpdateAt will throw.
+    var update = um.getUpdateAt(0)
+                   .QueryInterface(Components.interfaces.nsIPropertyBag);
+  } catch (e) {
+    // This should never happen.
+    Components.utils.reportError("Unable to find update: " + e);
+    return defaultOverridePage;
+  }
+
+  let actions = update.getProperty("actions");
+  // When the update doesn't specify actions fallback to the original behavior
+  // of displaying the default override page.
+  if (!actions)
+    return defaultOverridePage;
+
+  // The existence of silent or the non-existence of showURL in the actions both
+  // mean that an override page should not be displayed.
+  if (actions.indexOf("silent") != -1 || actions.indexOf("showURL") == -1)
+    return "";
+
+  return update.getProperty("openURL") || defaultOverridePage;
+}
+
 // Copies a pref override file into the user's profile pref-override folder,
 // and then tells the pref service to reload its default prefs.
 function copyPrefOverride() {
   try {
     var fileLocator = Components.classes["@mozilla.org/file/directory_service;1"]
                                 .getService(Components.interfaces.nsIProperties);
     const NS_APP_EXISTING_PREF_OVERRIDE = "ExistingPrefOverride";
     var prefOverride = fileLocator.get(NS_APP_EXISTING_PREF_OVERRIDE,
@@ -531,18 +566,20 @@ var nsBrowserContentHandler = {
           copyPrefOverride();
 
           // Check whether we have a session to restore. If we do, we assume
           // that this is an "update" session.
           var ss = Components.classes["@mozilla.org/browser/sessionstartup;1"]
                              .getService(Components.interfaces.nsISessionStartup);
           haveUpdateSession = ss.doRestore();
           overridePage = formatter.formatURLPref("startup.homepage_override_url");
+          if (prefb.prefHasUserValue("app.update.postupdate"))
+            overridePage = getPostUpdateOverridePage(overridePage);
           break;
-    }
+      }
     } catch (ex) {}
 
     // formatURLPref might return "about:blank" if getting the pref fails
     if (overridePage == "about:blank")
       overridePage = "";
 
     var startPage = "";
     try {

--- a/browser/components/nsBrowserGlue.js
+++ b/browser/components/nsBrowserGlue.js
@@ -21,16 +21,17 @@
 # Contributor(s):
 #   Giorgio Maone <g.maone@informaction.com>
 #   Seth Spitzer <sspitzer@mozilla.com>
 #   Asaf Romano <mano@mozilla.com>
 #   Marco Bonardo <mak77@bonardo.net>
 #   Dietrich Ayala <dietrich@mozilla.com>
 #   Ehsan Akhgari <ehsan.akhgari@gmail.com>
 #   Nils Maier <maierman@web.de>
+#   Robert Strong <robert.bugzilla@gmail.com>
 #
 # Alternatively, the contents of this file may be used under the terms of
 # either the GNU General Public License Version 2 or later (the "GPL"), or
 # the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 # in which case the provisions of the GPL or the LGPL are applicable instead
 # of those above. If you wish to allow use of your version of this file only
 # under the terms of either the GPL or the LGPL, and not to allow others to
 # use your version of this file under the terms of the MPL, indicate your
@@ -212,16 +213,23 @@ BrowserGlue.prototype = {
         break;
       case "bookmarks-restore-success":
       case "bookmarks-restore-failed":
         this._observerService.removeObserver(this, "bookmarks-restore-success");
         this._observerService.removeObserver(this, "bookmarks-restore-failed");
         if (topic == "bookmarks-restore-success" && data == "html-initial")
           this.ensurePlacesDefaultQueriesInitialized();
         break;
+      case "browser-glue-test": // used by tests
+        if (data == "post-update-notification") {
+          if (this._prefs.prefHasUserValue("app.update.postupdate"))
+            this._showUpdateNotification();
+          break;
+        }
+        break;
     }
   }, 
 
   // initialization (called on application startup) 
   _init: function BG__init() {
     // observer registration
     const osvr = this._observerService;
     osvr.addObserver(this, "xpcom-shutdown", false);
@@ -334,16 +342,20 @@ BrowserGlue.prototype = {
   },
 
   // Browser startup complete. All initial windows have opened.
   _onBrowserStartup: function BG__onBrowserStartup() {
     // Show about:rights notification, if needed.
     if (this._shouldShowRights())
       this._showRightsNotification();
 
+    // Show update notification, if needed.
+    if (this._prefs.prefHasUserValue("app.update.postupdate"))
+      this._showUpdateNotification();
+
     // If new add-ons were installed during startup open the add-ons manager.
     if (this._prefs.prefHasUserValue(PREF_EM_NEW_ADDONS_LIST)) {
       var args = Cc["@mozilla.org/supports-array;1"].
                  createInstance(Ci.nsISupportsArray);
       var str = Cc["@mozilla.org/supports-string;1"].
                 createInstance(Ci.nsISupportsString);
       str.data = "";
       args.AppendElement(str);
@@ -571,17 +583,133 @@ BrowserGlue.prototype = {
 
     // Set pref to indicate we've shown the notification.
     var currentVersion = this._prefs.getIntPref("browser.rights.version");
     this._prefs.setBoolPref("browser.rights." + currentVersion + ".shown", true);
 
     var box = notifyBox.appendNotification(notifyRightsText, "about-rights", null, notifyBox.PRIORITY_INFO_LOW, buttons);
     box.persistence = 3; // arbitrary number, just so bar sticks around for a bit
   },
-  
+
+  _showUpdateNotification: function BG__showUpdateNotification() {
+    this._prefs.clearUserPref("app.update.postupdate");
+
+    var um = Cc["@mozilla.org/updates/update-manager;1"].
+             getService(Ci.nsIUpdateManager);
+    try {
+      // If the updates.xml file is deleted then getUpdateAt will throw.
+      var update = um.getUpdateAt(0).QueryInterface(Ci.nsIPropertyBag);
+    }
+    catch (e) {
+      // This should never happen.
+      Cu.reportError("Unable to find update: " + e);
+      return;
+    }
+
+    var actions = update.getProperty("actions");
+    if (!actions || actions.indexOf("silent") != -1)
+      return;
+
+    var formatter = Cc["@mozilla.org/toolkit/URLFormatterService;1"].
+                    getService(Ci.nsIURLFormatter);
+    var browserBundle = this._bundleService.
+                        createBundle("chrome://browser/locale/browser.properties");
+    var brandBundle = this._bundleService.
+                      createBundle("chrome://branding/locale/brand.properties");
+    var appName = brandBundle.GetStringFromName("brandShortName");
+
+    function getNotifyString(aPropData) {
+      var propValue = update.getProperty(aPropData.propName);
+      if (!propValue) {
+        if (aPropData.prefName)
+          propValue = formatter.formatURLPref(aPropData.prefName);
+        else if (aPropData.stringParams)
+          propValue = browserBundle.formatStringFromName(aPropData.stringName,
+                                                         aPropData.stringParams,
+                                                         aPropData.stringParams.length);
+        else
+          propValue = browserBundle.GetStringFromName(aPropData.stringName);
+      }
+      return propValue;
+    }
+
+    if (actions.indexOf("showNotification") != -1) {
+      let text = getNotifyString({propName: "notificationText",
+                                  stringName: "puNotifyText",
+                                  stringParams: [appName]});
+      let url = getNotifyString({propName: "notificationURL",
+                                 prefName: "startup.homepage_override_url"});
+      let label = getNotifyString({propName: "notificationButtonLabel",
+                                   stringName: "pu.notifyButton.label"});
+      let key = getNotifyString({propName: "notificationButtonAccessKey",
+                                 stringName: "pu.notifyButton.accesskey"});
+
+      let win = this.getMostRecentBrowserWindow();
+      let browser = win.gBrowser; // for closure in notification bar callback
+      let notifyBox = browser.getNotificationBox();
+
+      let buttons = [
+                      {
+                        label:     label,
+                        accessKey: key,
+                        popup:     null,
+                        callback: function(aNotificationBar, aButton) {
+                          browser.selectedTab = browser.addTab(url);
+                        }
+                      }
+                    ];
+
+      let box = notifyBox.appendNotification(text, "post-update-notification",
+                                             null, notifyBox.PRIORITY_INFO_LOW,
+                                             buttons);
+      box.persistence = 3;
+    }
+
+    if (actions.indexOf("showAlert") == -1)
+      return;
+
+    let notifier;
+    try {
+      notifier = Cc["@mozilla.org/alerts-service;1"].
+                 getService(Ci.nsIAlertsService);
+    }
+    catch (e) {
+      // nsIAlertsService is not available for this platform
+      return;
+    }
+
+    let title = getNotifyString({propName: "alertTitle",
+                                 stringName: "puAlertTitle",
+                                 stringParams: [appName]});
+    let text = getNotifyString({propName: "alertText",
+                                stringName: "puAlertText",
+                                stringParams: [appName]});
+    let url = getNotifyString({propName: "alertURL",
+                               prefName: "startup.homepage_override_url"});
+
+    var self = this;
+    function clickCallback(subject, topic, data) {
+      // This callback will be called twice but only once with this topic
+      if (topic != "alertclickcallback")
+        return;
+      let win = self.getMostRecentBrowserWindow();
+      let browser = win.gBrowser;
+      browser.selectedTab = browser.addTab(data);
+    }
+
+    try {
+      // This will throw NS_ERROR_NOT_AVAILABLE if the notification cannot
+      // be displayed per the idl.
+      notifier.showAlertNotification("post-update-notification", title, text,
+                                     true, url, clickCallback);
+    }
+    catch (e) {
+    }
+  },
+
   _showPluginUpdatePage: function BG__showPluginUpdatePage() {
     this._prefs.setBoolPref(PREF_PLUGINS_NOTIFYUSER, false);
 
     var formatter = Cc["@mozilla.org/toolkit/URLFormatterService;1"].
                     getService(Ci.nsIURLFormatter);
     var updateUrl = formatter.formatURLPref(PREF_PLUGINS_UPDATEURL);
 
     var win = this.getMostRecentBrowserWindow();

new file mode 100644
--- /dev/null
+++ b/browser/components/test/Makefile.in
@@ -0,0 +1,48 @@
+#
+# ***** BEGIN LICENSE BLOCK *****
+# Version: MPL 1.1/GPL 2.0/LGPL 2.1
+#
+# The contents of this file are subject to the Mozilla Public License Version
+# 1.1 (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+# http://www.mozilla.org/MPL/
+#
+# Software distributed under the License is distributed on an "AS IS" basis,
+# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+# for the specific language governing rights and limitations under the
+# License.
+#
+# The Original Code is mozilla.org code.
+#
+# The Initial Developer of the Original Code is
+# the Mozilla Foundation.
+# Portions created by the Initial Developer are Copyright (C) 2010
+# the Initial Developer. All Rights Reserved.
+#
+# Contributor(s):
+#   Robert Strong <robert.bugzilla@gmail.com> (Original Author)
+#
+# Alternatively, the contents of this file may be used under the terms of
+# either of the GNU General Public License Version 2 or later (the "GPL"),
+# or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+# in which case the provisions of the GPL or the LGPL are applicable instead
+# of those above. If you wish to allow use of your version of this file only
+# under the terms of either the GPL or the LGPL, and not to allow others to
+# use your version of this file under the terms of the MPL, indicate your
+# decision by deleting the provisions above and replace them with the notice
+# and other provisions required by the GPL or the LGPL. If you do not delete
+# the provisions above, a recipient may use your version of this file under
+# the terms of any one of the MPL, the GPL or the LGPL.
+#
+# ***** END LICENSE BLOCK *****
+
+DEPTH     = ../../..
+topsrcdir = @top_srcdir@
+srcdir    = @srcdir@
+VPATH     = @srcdir@
+
+include $(DEPTH)/config/autoconf.mk
+
+DIRS = browser
+
+include $(topsrcdir)/config/rules.mk

new file mode 100644
--- /dev/null
+++ b/browser/components/test/browser/Makefile.in
@@ -0,0 +1,52 @@
+# ***** BEGIN LICENSE BLOCK *****
+# Version: MPL 1.1/GPL 2.0/LGPL 2.1
+#
+# The contents of this file are subject to the Mozilla Public License Version
+# 1.1 (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+# http://www.mozilla.org/MPL/
+#
+# Software distributed under the License is distributed on an "AS IS" basis,
+# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+# for the specific language governing rights and limitations under the
+# License.
+#
+# The Original Code is mozilla.org code.
+#
+# The Initial Developer of the Original Code is
+# the Mozilla Foundation.
+# Portions created by the Initial Developer are Copyright (C) 2010
+# the Initial Developer. All Rights Reserved.
+#
+# Contributor(s):
+#   Robert Strong <robert.bugzilla@gmail.com> (Original Author)
+#
+# Alternatively, the contents of this file may be used under the terms of
+# either of the GNU General Public License Version 2 or later (the "GPL"),
+# or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+# in which case the provisions of the GPL or the LGPL are applicable instead
+# of those above. If you wish to allow use of your version of this file only
+# under the terms of either the GPL or the LGPL, and not to allow others to
+# use your version of this file under the terms of the MPL, indicate your
+# decision by deleting the provisions above and replace them with the notice
+# and other provisions required by the GPL or the LGPL. If you do not delete
+# the provisions above, a recipient may use your version of this file under
+# the terms of any one of the MPL, the GPL or the LGPL.
+#
+# ***** END LICENSE BLOCK *****
+
+DEPTH     = ../../../..
+topsrcdir = @top_srcdir@
+srcdir    = @srcdir@
+VPATH     = @srcdir@
+relativesrcdir  = browser/components/test/browser
+
+include $(DEPTH)/config/autoconf.mk
+include $(topsrcdir)/config/rules.mk
+
+_BROWSER_TEST_FILES = \
+  browser_bug538331.js \
+  $(NULL)
+
+libs:: $(_BROWSER_TEST_FILES)
+	$(INSTALL) $(foreach f,$^,"$f") $(DEPTH)/_tests/testing/mochitest/browser/$(relativesrcdir)

new file mode 100644
--- /dev/null
+++ b/browser/components/test/browser/browser_bug538331.js
@@ -0,0 +1,373 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+const PREF_POSTUPDATE = "app.update.postupdate";
+const PREF_MSTONE = "browser.startup.homepage_override.mstone";
+const PREF_OVERRIDE_URL = "startup.homepage_override_url";
+
+const DEFAULT_PREF_URL = "http://pref.example.com/";
+const DEFAULT_UPDATE_URL = "http://example.com/";
+
+const XML_EMPTY = "<?xml version=\"1.0\"?><updates xmlns=" +
+                  "\"http://www.mozilla.org/2005/app-update\"></updates>";
+
+const XML_PREFIX =  "<updates xmlns=\"http://www.mozilla.org/2005/app-update\"" +
+                    "><update appVersion=\"1.0\" buildID=\"20080811053724\" " +
+                    "channel=\"nightly\" displayVersion=\"Version 1.0\" " +
+                    "extensionVersion=\"1.0\" installDate=\"1238441400314\" " +
+                    "isCompleteUpdate=\"true\" name=\"Update Test 1.0\" " +
+                    "serviceURL=\"https://example.com/\" showNeverForVersion=" +
+                    "\"false\" showPrompt=\"false\" showSurvey=\"false\" type=" +
+                    "\"minor\" version=\"version 1.0\" detailsURL=" +
+                    "\"http://example.com/\" previousAppVersion=\"1.0\" " +
+                    "statusText=\"The Update was successfully installed\" " +
+                    "foregroundDownload=\"true\"";
+
+const XML_SUFFIX = "><patch type=\"complete\" URL=\"http://example.com/\" " +
+                   "hashFunction=\"MD5\" hashValue=" +
+                   "\"6232cd43a1c77e30191c53a329a3f99d\" size=\"775\" " +
+                   "selected=\"true\" state=\"succeeded\"/></update></updates>";
+
+// nsBrowserContentHandler.js defaultArgs tests
+const BCH_TESTS = [
+  {
+    description: "no mstone change and no update",
+    noPostUpdatePref: true,
+    noMstoneChange: true
+  }, {
+    description: "mstone changed and no update",
+    noPostUpdatePref: true,
+    prefURL: DEFAULT_PREF_URL
+  }, {
+    description: "no mstone change and update with 'showURL' for actions",
+    actions: "showURL",
+    noMstoneChange: true
+  }, {
+    description: "update without actions",
+    prefURL: DEFAULT_PREF_URL
+  }, {
+    description: "update with 'showURL' for actions",
+    actions: "showURL",
+    prefURL: DEFAULT_PREF_URL
+  }, {
+    description: "update with 'showURL' for actions and openURL",
+    actions: "showURL",
+    openURL: DEFAULT_UPDATE_URL
+    }, {
+    description: "update with 'showURL showAlert' for actions",
+    actions: "showAlert showURL",
+    prefURL: DEFAULT_PREF_URL
+  }, {
+    description: "update with 'showAlert showURL' for actions and openURL",
+    actions: "showAlert showURL",
+    openURL: DEFAULT_UPDATE_URL
+  }, {
+    description: "update with 'showURL showNotification' for actions",
+    actions: "showURL showNotification",
+    prefURL: DEFAULT_PREF_URL
+  }, {
+    description: "update with 'showNotification showURL' for actions and " +
+                 "openURL",
+    actions: "showNotification showURL",
+    openURL: DEFAULT_UPDATE_URL
+  }, {
+    description: "update with 'showAlert showURL showNotification' for actions",
+    actions: "showAlert showURL showNotification",
+    prefURL: DEFAULT_PREF_URL
+  }, {
+    description: "update with 'showNotification showURL showAlert' for " +
+                 "actions and openURL",
+    actions: "showNotification showURL showAlert",
+    openURL: DEFAULT_UPDATE_URL
+  }, {
+    description: "update with 'showAlert' for actions",
+    actions: "showAlert"
+  }, {
+    description: "update with 'showAlert showNotification' for actions",
+    actions: "showAlert showNotification"
+  }, {
+    description: "update with 'showNotification' for actions",
+    actions: "showNotification"
+  }, {
+    description: "update with 'showNotification showAlert' for actions",
+    actions: "showNotification showAlert"
+  }, {
+    description: "update with 'silent' for actions",
+    actions: "silent"
+  }, {
+    description: "update with 'silent showURL showAlert showNotification' " +
+                 "for actions and openURL",
+    actions: "silent showURL showAlert showNotification"
+  }
+];
+
+var gOriginalMStone;
+var gOriginalOverrideURL;
+
+__defineGetter__("gBG", function() {
+  delete this.gBG;
+  return this.gBG = Cc["@mozilla.org/browser/browserglue;1"].
+                    getService(Ci.nsIBrowserGlue).
+                    QueryInterface(Ci.nsIObserver);
+});
+
+function test()
+{
+  waitForExplicitFinish();
+
+  if (gPrefService.prefHasUserValue(PREF_MSTONE)) {
+    gOriginalMStone = gPrefService.getCharPref(PREF_MSTONE);
+  }
+
+  if (gPrefService.prefHasUserValue(PREF_OVERRIDE_URL)) {
+    gOriginalOverrideURL = gPrefService.getCharPref(PREF_OVERRIDE_URL);
+  }
+
+  testDefaultArgs();
+}
+
+function finish_test()
+{
+  // Reset browser.startup.homepage_override.mstone to the original value or
+  // clear it if it didn't exist.
+  if (gOriginalMStone) {
+    gPrefService.setCharPref(PREF_MSTONE, gOriginalMStone);
+  } else if (gPrefService.prefHasUserValue(PREF_MSTONE)) {
+    gPrefService.clearUserPref(PREF_MSTONE);
+  }
+
+  // Reset startup.homepage_override_url to the original value or clear it if
+  // it didn't exist.
+  if (gOriginalOverrideURL) {
+    gPrefService.setCharPref(PREF_OVERRIDE_URL, gOriginalOverrideURL);
+  } else if (gPrefService.prefHasUserValue(PREF_OVERRIDE_URL)) {
+    gPrefService.clearUserPref(PREF_OVERRIDE_URL);
+  }
+
+  writeUpdatesToXMLFile(XML_EMPTY);
+  reloadUpdateManagerData();
+
+  finish();
+}
+
+// Test the defaultArgs returned by nsBrowserContentHandler after an update
+function testDefaultArgs()
+{
+  // Clear any pre-existing override in defaultArgs that are hanging around.
+  // This will also set the browser.startup.homepage_override.mstone preference
+  // if it isn't already set.
+  Cc["@mozilla.org/browser/clh;1"].getService(Ci.nsIBrowserHandler).defaultArgs;
+
+  let originalMstone = gPrefService.getCharPref(PREF_MSTONE);
+
+  gPrefService.setCharPref(PREF_OVERRIDE_URL, DEFAULT_PREF_URL);
+
+  writeUpdatesToXMLFile(XML_EMPTY);
+  reloadUpdateManagerData();
+
+  for (let i = 0; i < BCH_TESTS.length; i++) {
+    let test = BCH_TESTS[i];
+    ok(true, "Test nsBrowserContentHandler " + (i + 1) + ": " + test.description);
+
+    if (test.actions) {
+      let actionsXML = " actions=\"" + test.actions + "\"";
+      if (test.openURL) {
+        actionsXML += " openURL=\"" + test.openURL + "\"";
+      }
+      writeUpdatesToXMLFile(XML_PREFIX + actionsXML + XML_SUFFIX);
+    } else {
+      writeUpdatesToXMLFile(XML_EMPTY);
+    }
+
+    reloadUpdateManagerData();
+
+    let noOverrideArgs = Cc["@mozilla.org/browser/clh;1"].
+                         getService(Ci.nsIBrowserHandler).defaultArgs;
+
+    let overrideArgs = "";
+    if (test.prefURL) {
+      overrideArgs = test.prefURL;
+    } else if (test.openURL) {
+      overrideArgs = test.openURL;
+    }
+
+    if (overrideArgs == "" && noOverrideArgs) {
+      overrideArgs = noOverrideArgs;
+    } else if (noOverrideArgs) {
+      overrideArgs += "|" + noOverrideArgs;
+    }
+
+    if (test.noMstoneChange === undefined) {
+      gPrefService.setCharPref(PREF_MSTONE, "PreviousMilestone");
+    }
+
+    if (test.noPostUpdatePref == undefined) {
+      gPrefService.setBoolPref(PREF_POSTUPDATE, true);
+    }
+
+    let defaultArgs = Cc["@mozilla.org/browser/clh;1"].
+                      getService(Ci.nsIBrowserHandler).defaultArgs;
+    is(defaultArgs, overrideArgs, "correct value returned by defaultArgs");
+
+    if (test.noMstoneChange === undefined || test.noMstoneChange != true) {
+      let newMstone = gPrefService.getCharPref(PREF_MSTONE);
+      is(originalMstone, newMstone, "preference " + PREF_MSTONE +
+         " should have been updated");
+    }
+
+    if (gPrefService.prefHasUserValue(PREF_POSTUPDATE)) {
+      gPrefService.clearUserPref(PREF_POSTUPDATE);
+    }
+  }
+
+  testShowNotification();
+}
+
+// nsBrowserGlue.js _showUpdateNotification notification tests
+const BG_NOTIFY_TESTS = [
+  {
+    description: "'silent showNotification' actions should not display a notification",
+    actions: "silent showNotification"
+  }, {
+    description: "'showNotification' for actions should display a notification",
+    actions: "showNotification"
+  }, {
+    description: "no actions and empty updates.xml",
+  }, {
+    description: "'showAlert' for actions should not display a notification",
+    actions: "showAlert"
+  }, {
+    // This test MUST be the last test in the array to test opening the url
+    // provided by the updates.xml.
+    description: "'showNotification' for actions with custom notification " +
+                 "attributes should display a notification",
+    actions: "showNotification",
+    notificationText: "notification text",
+    notificationURL: DEFAULT_UPDATE_URL,
+    notificationButtonLabel: "button label",
+    notificationButtonAccessKey: "b"
+  }
+];
+
+// Test showing a notification after an update
+// _showUpdateNotification in nsBrowserGlue.js
+function testShowNotification()
+{
+  let gTestBrowser = gBrowser.selectedBrowser;
+  let notifyBox = gBrowser.getNotificationBox(gTestBrowser);
+
+  for (let i = 0; i < BG_NOTIFY_TESTS.length; i++) {
+    let test = BG_NOTIFY_TESTS[i];
+    ok(true, "Test showNotification " + (i + 1) + ": " + test.description);
+
+    if (test.actions) {
+      let actionsXML = " actions=\"" + test.actions + "\"";
+      if (test.notificationText) {
+        actionsXML += " notificationText=\"" + test.notificationText + "\"";
+      }
+      if (test.notificationURL) {
+        actionsXML += " notificationURL=\"" + test.notificationURL + "\"";
+      }
+      if (test.notificationButtonLabel) {
+        actionsXML += " notificationButtonLabel=\"" + test.notificationButtonLabel + "\"";
+      }
+      if (test.notificationButtonAccessKey) {
+        actionsXML += " notificationButtonAccessKey=\"" + test.notificationButtonAccessKey + "\"";
+      }
+      writeUpdatesToXMLFile(XML_PREFIX + actionsXML + XML_SUFFIX);
+    } else {
+      writeUpdatesToXMLFile(XML_EMPTY);
+    }
+
+    reloadUpdateManagerData();
+    gPrefService.setBoolPref(PREF_POSTUPDATE, true);
+
+    gBG.observe(null, "browser-glue-test", "post-update-notification");
+
+    let updateBox = notifyBox.getNotificationWithValue("post-update-notification");
+    if (test.actions && test.actions.indexOf("showNotification") != -1 &&
+        test.actions.indexOf("silent") == -1) {
+      ok(updateBox, "Update notification box should have been displayed");
+      if (updateBox) {
+        if (test.notificationText) {
+          is(updateBox.label, test.notificationText, "Update notification box " +
+             "should have the label provided by the update");
+        }
+        if (test.notificationButtonLabel) {
+          var button = updateBox.getElementsByTagName("button").item(0);
+          is(button.label, test.notificationButtonLabel, "Update notification " +
+             "box button should have the label provided by the update");
+          if (test.notificationButtonAccessKey) {
+            let accessKey = button.getAttribute("accesskey");
+            is(accessKey, test.notificationButtonAccessKey, "Update " +
+               "notification box button should have the accesskey " +
+               "provided by the update");
+          }
+        }
+        // The last test opens an url and verifies the url from the updates.xml
+        // is correct.
+        if (i == (BG_NOTIFY_TESTS.length - 1)) {
+          button.click();
+          gBrowser.selectedBrowser.addEventListener("load", testNotificationURL, true);
+        }
+      } else if (i == (BG_NOTIFY_TESTS.length - 1)) {
+        // If updateBox is null the test has already reported errors so bail
+        finish_test();
+      }
+      notifyBox.removeAllNotifications(true);
+    } else {
+      ok(!updateBox, "Update notification box should not have been displayed");
+    }
+
+    let prefHasUserValue = gPrefService.prefHasUserValue(PREF_POSTUPDATE);
+    is(prefHasUserValue, false, "preference " + PREF_POSTUPDATE +
+       " shouldn't have a user value");
+  }
+}
+
+// Test opening the url provided by the updates.xml in the last test
+function testNotificationURL()
+{
+  ok(true, "Test testNotificationURL: clicking the notification button " +
+           "opened the url specified by the update");
+  let href = gBrowser.selectedBrowser.contentWindow.location.href;
+  let expectedURL = BG_NOTIFY_TESTS[BG_NOTIFY_TESTS.length - 1].notificationURL;
+  is(href, expectedURL, "The url opened from the notification should be the " +
+     "url provided by the update");
+  gBrowser.removeCurrentTab();
+  window.focus();
+  finish_test();
+}
+
+/* Reloads the update metadata from disk */
+function reloadUpdateManagerData()
+{
+  Cc["@mozilla.org/updates/update-manager;1"].getService(Ci.nsIUpdateManager).
+  QueryInterface(Ci.nsIObserver).observe(null, "um-reload-update-data", "");
+}
+
+
+function writeUpdatesToXMLFile(aText)
+{
+  const PERMS_FILE = 0644;
+
+  const MODE_WRONLY   = 0x02;
+  const MODE_CREATE   = 0x08;
+  const MODE_TRUNCATE = 0x20;
+
+  let file = Cc["@mozilla.org/file/directory_service;1"].
+             getService(Ci.nsIProperties).
+             get("XCurProcD", Ci.nsIFile);
+  file.append("updates.xml");
+  let fos = Cc["@mozilla.org/network/file-output-stream;1"].
+            createInstance(Ci.nsIFileOutputStream);
+  if (!file.exists()) {
+    file.create(Ci.nsILocalFile.NORMAL_FILE_TYPE, PERMS_FILE);
+  }
+  fos.init(file, MODE_WRONLY | MODE_CREATE | MODE_TRUNCATE, PERMS_FILE, 0);
+  fos.write(aText, aText.length);
+  fos.close();
+}

--- a/browser/locales/en-US/chrome/browser/browser.properties
+++ b/browser/locales/en-US/chrome/browser/browser.properties
@@ -186,16 +186,24 @@ editBookmarkPanel.editBookmarkTitle=Edit
 
 # LOCALIZATION NOTE (editBookmark.removeBookmarks.label)
 # Semi-colon list of plural forms. Replacement for #1 is
 # the number of bookmarks to be removed.
 # If this causes problems with localization you can also do "Remove Bookmarks (#1)"
 # instead of "Remove #1 Bookmarks".
 editBookmark.removeBookmarks.label=Remove Bookmark;Remove #1 Bookmarks
 
+# Post Update Notifications
+pu.notifyButton.label=Details…
+pu.notifyButton.accesskey=D
+# LOCALIZATION NOTE %S will be replaced by the short name of the application.
+puNotifyText=%S has been updated
+puAlertTitle=%S Updated
+puAlertText=Click here for details
+
 # Geolocation UI
 
 # LOCALIZATION NOTE (geolocation.shareLocation geolocation.dontShareLocation): 
 #If you're having trouble with the word Share, please use Allow and Block in your language.
 geolocation.shareLocation=Share Location
 geolocation.shareLocation.accesskey=a
 geolocation.dontShareLocation=Don't Share
 geolocation.dontShareLocation.accesskey=o