Make Menu.findMenuItem_ return the first MenuItem.

ui/webui/resources/js/cr/ui/menu.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 cr.define('cr.ui', function() {
 
   /** @const */ var MenuItem = cr.ui.MenuItem;
 
   /**
    * Creates a new menu element. Menu dispatches all commands on the element it
@@ skipping 70 matching lines @@
     },
 
     /**
      * Walks up the ancestors of |node| until a menu item belonging to this menu
      * is found.
      * @param {Node} node The node to start searching from.
      * @return {cr.ui.MenuItem} The found menu item or null.
      * @private
      */
     findMenuItem_: function(node) {
-      while (node && node.parentNode != this) {
+      while (node && node.parentNode != this && !(node instanceof MenuItem)) {
         node = node.parentNode;
       }
       return node ? assertInstanceof(node, MenuItem) : null;
     },
 
     /**
      * Handles mouseover events and selects the hovered item.
      * @param {Event} e The mouseover event.
      * @private
      */
@@ skipping 171 matching lines @@
   /**
    * Selector for children which are menu items.
    */
   cr.defineProperty(Menu, 'menuItemSelector', cr.PropertyKind.ATTR);
 
   // Export
   return {
     Menu: Menu
   };
 });