Should not unregister BookmarkTreeItem from lookup table on handling moved event

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

Index: chrome/browser/resources/bookmark_manager/js/bmm/bookmark_tree.js
diff --git a/chrome/browser/resources/bookmark_manager/js/bmm/bookmark_tree.js b/chrome/browser/resources/bookmark_manager/js/bmm/bookmark_tree.js
index 3f235f9b02881b6fa19b5a86c1370b3b8baa573f..aeb8b3fac7a3fc7b19a9f8261c8d1dbcfafcd98a 100644
--- a/chrome/browser/resources/bookmark_manager/js/bmm/bookmark_tree.js
+++ b/chrome/browser/resources/bookmark_manager/js/bmm/bookmark_tree.js
@@ -102,13 +102,6 @@ cr.define('bmm', function() {
   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}