MD Bookmarks: Pull context menu into separate element

chrome/browser/resources/md_bookmarks/item.js

 // Copyright 2016 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.
 
 Polymer({
   is: 'bookmarks-item',
 
   behaviors: [
     bookmarks.StoreClient,
   ],
@@ skipping 53 matching lines @@
    */
   onContextMenu_: function(e) {
     e.preventDefault();
     if (!this.isSelectedItem_) {
       this.dispatch(bookmarks.actions.selectItem(
           this.itemId, false, false, this.getState()));
     }
     this.fire('open-item-menu', {
       x: e.clientX,
       y: e.clientY,
-      item: this.item_,
     });
   },
 
   /**
    * @param {Event} e
    * @private
    */
   onMenuButtonClick_: function(e) {
     e.stopPropagation();
     this.dispatch(bookmarks.actions.selectItem(
         this.itemId, false, false, this.getState()));
     this.fire('open-item-menu', {
       targetElement: e.target,
-      item: this.item_,
     });
   },
 
   /**
    * @param {Event} e
    * @private
    */
   onMenuButtonDblClick_: function(e) {
     e.stopPropagation();
   },
@@ skipping 35 matching lines @@
   },
 
   /**
    * @param {string} url
    * @private
    */
   updateFavicon_: function(url) {
     this.$.icon.style.backgroundImage = cr.icon.getFavicon(url);
   },
 });