Add "check for updates" to main menu and AppMenu

Tag #963.

application/palemoon/base/content/baseMenuOverlay.xul

@@ -67,6 +67,12 @@
                   label="&helpSafeMode.label;"
                   oncommand="restart(true);"/>
         <menuseparator id="aboutSeparator"/>
+#ifdef MOZ_UPDATER
+        <menuitem id="helpCheckForUpdates"
+                  accesskey="&checkForUpdates.accesskey;"
+                  label="&checkForUpdates.label;"
+                  oncommand="checkForUpdates();"/>
+#endif
         <menuitem id="aboutName"
                   accesskey="&aboutProduct.accesskey;"
                   label="&aboutProduct.label;"

application/palemoon/base/content/browser-appmenu.inc

@@ -359,6 +359,11 @@
                       label="&appMenuSafeMode.label;"
                       oncommand="restart(true);"/>
             <menuseparator/>
+#ifdef MOZ_UPDATER
+            <menuitem id="appmenu_checkForUpdates"
+                      label="&checkForUpdates.label;"
+                      oncommand="checkForUpdates();"/>
+#endif
             <menuitem id="appmenu_about"
                       label="&aboutProduct.label;"
                       oncommand="openAboutDialog();"/>

application/palemoon/base/content/utilityOverlay.js

@@ -590,6 +590,29 @@ function openAdvancedPreferences(tabID)
   openPreferences("paneAdvanced", { "advancedTab" : tabID });
 }
 
+#ifdef MOZ_UPDATER
+/**
+ * Opens the update manager and checks for updates to the application.
+ */
+function checkForUpdates()
+{
+  var um = 
+      Components.classes["@mozilla.org/updates/update-manager;1"].
+      getService(Components.interfaces.nsIUpdateManager);
+  var prompter = 
+      Components.classes["@mozilla.org/updates/update-prompt;1"].
+      createInstance(Components.interfaces.nsIUpdatePrompt);
+
+  // If there's an update ready to be applied, show the "Update Downloaded"
+  // UI instead and let the user know they have to restart the browser for
+  // the changes to be applied. 
+  if (um.activeUpdate && um.activeUpdate.state == "pending")
+    prompter.showUpdateDownloaded(um.activeUpdate);
+  else
+    prompter.checkForUpdates();
+}
+#endif
+
 /**
  * Opens the troubleshooting information (about:support) page for this version
  * of the application.

application/palemoon/locales/en-US/chrome/browser/baseMenuOverlay.dtd

@@ -25,6 +25,9 @@
 <!ENTITY helpTroubleshootingInfo.label      "Troubleshooting Information">
 <!ENTITY helpTroubleshootingInfo.accesskey  "T">
 
+<!ENTITY checkForUpdates.label       "Check for Updates…">
+<!ENTITY checkForUpdates.accesskey   "C">
+
 <!ENTITY helpFeedbackPage.label      "Submit Feedback…">
 <!ENTITY helpFeedbackPage.accesskey  "S">