Should not unregister BookmarkTreeItem from lookup table on handling moved event

chrome/browser/resources/bookmark_manager/js/bmm/bookmark_tree.js

 // Copyright (c) 2011 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('bmm', function() {
   /** @const */ var Tree = cr.ui.Tree;
   /** @const */ var TreeItem = cr.ui.TreeItem;
 
   var treeLookup = {};
@@ skipping 84 matching lines @@
       draggable: bookmarkNode.parentId != ROOT_ID
     });
     ti.__proto__ = BookmarkTreeItem.prototype;
     treeLookup[bookmarkNode.id] = ti;
     return ti;
   }
 
   BookmarkTreeItem.prototype = {
     __proto__: TreeItem.prototype,
 
-    /** @override */
-    remove: function(child) {
-      TreeItem.prototype.remove.call(this, child);
-      if (child.bookmarkNode)
-        delete treeLookup[child.bookmarkNode.id];
-    },
-
     /**
      * The ID of the bookmark this tree item represents.
      * @type {string}
      */
     get bookmarkId() {
       return this.bookmarkNode.id;
     }
   };
 
   /**
@@ skipping 165 matching lines @@
     }
   };
 
   return {
     BookmarkTree: BookmarkTree,
     BookmarkTreeItem: BookmarkTreeItem,
     treeLookup: treeLookup,
     tree: tree
   };
 });