Bookmark manager drag and drop frontend

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

 // Copyright (c) 2010 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() {
   // require cr.ui.define
   // require cr.ui.limitInputWidth.
   // require cr.ui.contextMenuHandler
   const List = cr.ui.List;
@@ skipping 43 matching lines @@
       cr.dispatchPropertyChange(this, 'parentId', parentId, oldParentId);
     },
 
     handleBookmarkCallback: function(items) {
       if (!items) {
         // Failed to load bookmarks. Most likely due to the bookmark beeing
         // removed.
         cr.dispatchSimpleEvent(this, 'invalidId');
         return;
       }
-      listLookup = {};
+      // Remove all fields without recreating the object since other code
+      // references it.
+      for (var id in listLookup){
+        delete listLookup[id];
+      }
       this.clear();
       var showFolder = this.showFolder();
       items.forEach(function(item) {
         var li = createListItem(item, showFolder);
         this.add(li);
       }, this);
       cr.dispatchSimpleEvent(this, 'load');
     },
 
     /**
@@ skipping 297 matching lines @@
         '<div><span class=folder></span></div>' +
         '</div>';
     return div.firstChild;
   })();
 
   return {
     BookmarkList: BookmarkList,
     listLookup: listLookup
   };
 });