diff -r 000000000000 -r 6474c204b198 browser/metro/base/content/commandUtil.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/browser/metro/base/content/commandUtil.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,164 @@
+/* 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/. */
+
+
+/**
+ * Command Updater
+ */
+var CommandUpdater = {
+  /**
+   * Gets a controller that can handle a particular command.
+   * @param   command
+   *          A command to locate a controller for, preferring controllers that
+   *          show the command as enabled.
+   * @returns In this order of precedence:
+   *            - the first controller supporting the specified command
+   *              associated with the focused element that advertises the
+   *              command as ENABLED
+   *            - the first controller supporting the specified command
+   *              associated with the global window that advertises the
+   *              command as ENABLED
+   *            - the first controller supporting the specified command
+   *              associated with the focused element
+   *            - the first controller supporting the specified command
+   *              associated with the global window
+   */
+  _getControllerForCommand: function(command) {
+    try {
+      var controller = top.document.commandDispatcher.getControllerForCommand(command);
+      if (controller && controller.isCommandEnabled(command))
+        return controller;
+    }
+    catch(e) {
+    }
+    var controllerCount = window.controllers.getControllerCount();
+    for (var i = 0; i < controllerCount; ++i) {
+      var current = window.controllers.getControllerAt(i);
+      try {
+        if (current.supportsCommand(command) && current.isCommandEnabled(command))
+          return current;
+      }
+      catch (e) {
+      }
+    }
+    return controller || window.controllers.getControllerForCommand(command);
+  },
+
+  /**
+   * Updates the state of a XUL <command> element for the specified command
+   * depending on its state.
+   * @param   command
+   *          The name of the command to update the XUL <command> element for
+   */
+  updateCommand: function(command) {
+    var enabled = false;
+    try {
+      var controller = this._getControllerForCommand(command);
+      if (controller) {
+        enabled = controller.isCommandEnabled(command);
+      }
+    }
+    catch(ex) { }
+
+    this.enableCommand(command, enabled);
+  },
+
+  /**
+   * Updates the state of a XUL <command> element for the specified command
+   * depending on its state.
+   * @param   command
+   *          The name of the command to update the XUL <command> element for
+   */
+  updateCommands: function(_commands) {
+    var commands = _commands.split(",");
+    for (var command in commands) {
+      this.updateCommand(commands[command]);
+    }
+  },
+
+  /**
+   * Enables or disables a XUL <command> element.
+   * @param   command
+   *          The name of the command to enable or disable
+   * @param   enabled
+   *          true if the command should be enabled, false otherwise.
+   */
+  enableCommand: function(command, enabled) {
+    var element = document.getElementById(command);
+    if (!element)
+      return;
+    if (enabled)
+      element.removeAttribute("disabled");
+    else
+      element.setAttribute("disabled", "true");
+  },
+
+  /**
+   * Performs the action associated with a specified command using the most
+   * relevant controller.
+   * @param   command
+   *          The command to perform.
+   */
+  doCommand: function(command) {
+    var controller = this._getControllerForCommand(command);
+    if (!controller)
+      return;
+    controller.doCommand(command);
+  },
+
+  /**
+   * Changes the label attribute for the specified command.
+   * @param   command
+   *          The command to update.
+   * @param   labelAttribute
+   *          The label value to use.
+   */
+  setMenuValue: function(command, labelAttribute) {
+    var commandNode = top.document.getElementById(command);
+    if (commandNode)
+    {
+      var label = commandNode.getAttribute(labelAttribute);
+      if ( label )
+        commandNode.setAttribute('label', label);
+    }
+  },
+
+  /**
+   * Changes the accesskey attribute for the specified command.
+   * @param   command
+   *          The command to update.
+   * @param   valueAttribute
+   *          The value attribute to use.
+   */
+  setAccessKey: function(command, valueAttribute) {
+    var commandNode = top.document.getElementById(command);
+    if (commandNode)
+    {
+      var value = commandNode.getAttribute(valueAttribute);
+      if ( value )
+        commandNode.setAttribute('accesskey', value);
+    }
+  },
+
+  /**
+   * Inform all the controllers attached to a node that an event has occurred
+   * (e.g. the tree controllers need to be informed of blur events so that they can change some of the
+   * menu items back to their default values)
+   * @param   node
+   *          The node receiving the event
+   * @param   event
+   *          The event.
+   */
+  onEvent: function(node, event) {
+    var numControllers = node.controllers.getControllerCount();
+    var controller;
+
+    for ( var controllerIndex = 0; controllerIndex < numControllers; controllerIndex++ )
+    {
+      controller = node.controllers.getControllerAt(controllerIndex);
+      if ( controller )
+        controller.onEvent(event);
+    }
+  }
+};