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

chrome/browser/resources/md_bookmarks/item.js

Index: chrome/browser/resources/md_bookmarks/item.js
diff --git a/chrome/browser/resources/md_bookmarks/item.js b/chrome/browser/resources/md_bookmarks/item.js
index 16a525ba02031a9c608cbe9bcca92dab58bb40d0..45ff2b6f76c836e5f2f7fa5f4e4711d54d41689c 100644
--- a/chrome/browser/resources/md_bookmarks/item.js
+++ b/chrome/browser/resources/md_bookmarks/item.js
@@ -12,7 +12,7 @@ Polymer({
   properties: {
     itemId: {
       type: String,
-      observer: 'updateFromStore',
+      observer: 'onItemIdChanged_',
     },
 
     /** @private {BookmarkNode} */
@@ -61,6 +61,14 @@ Polymer({
   },
 
   /** @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);
   },