MD Bookmarks: Update URL router to work in new data binding system

chrome/browser/resources/md_bookmarks/toolbar.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-toolbar',
 
   behaviors: [
     bookmarks.StoreClient,
   ],
@@ skipping 64 matching lines @@
     var menu = /** @type {!CrActionMenuElement} */ (this.$.dropdown);
     menu.close();
   },
 
   /**
    * @param {Event} e
    * @private
    */
   onSearchChanged_: function(e) {
     var searchTerm = /** @type {string} */ (e.detail);
-    this.dispatch(bookmarks.actions.setSearchTerm(searchTerm));
+    if (searchTerm != this.searchTerm_)
+      this.dispatch(bookmarks.actions.setSearchTerm(searchTerm));
   },
 
   onSidebarWidthChanged_: function() {
     this.style.setProperty('--sidebar-width', this.sidebarWidth);
   },
 
   /** @private */
   onSearchTermChanged_: function() {
     this.searchField.setValue(this.searchTerm_ || '');
   },
 });