MD Bookmarks: Implement search and selection in new data flow system

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,
   ],
 
   properties: {
     itemId: {
       type: String,
-      observer: 'updateFromStore',
+      observer: 'onItemIdChanged_',
     },
 
     /** @private {BookmarkNode} */
     item_: {
       type: Object,
       observer: 'onItemChanged_',
     },
 
     /** @private */
     isSelectedItem_: {
@@ skipping 28 matching lines @@
    */
   onMenuButtonOpenClick_: function(e) {
     e.stopPropagation();
     this.fire('open-item-menu', {
       target: e.target,
       item: this.item_,
     });
   },
 
   /** @private */
+  onItemIdChanged_: function() {
+    // TODO(tsergeant): Add a histogram to measure whether this assertion fails
+    // for real users.
+    assert(this.getState().nodes[this.itemId]);
+    this.updateFromStore();
+  },
+
+  /** @private */
   onItemChanged_: function() {
     this.isFolder_ = !(this.item_.url);
   },
 
   /**
    * @param {Event} e
    * @private
    */
   onClick_: function(e) {
     this.fire('select-item', {
@@ skipping 15 matching lines @@
   },
 
   /**
    * @param {string} url
    * @private
    */
   updateFavicon_: function(url) {
     this.$.icon.style.backgroundImage = cr.icon.getFavicon(url);
   },
 });