MD Bookmarks: Update a couple of TODOs

chrome/browser/resources/md_bookmarks/store_client.js

 // Copyright 2017 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.
 
 /**
  * @fileoverview Defines StoreClient, a Polymer behavior to tie a front-end
  * element to back-end data from the store.
  */
 
 cr.define('bookmarks', function() {
@@ skipping 31 matching lines @@
      * getter function returns |undefined|, no changes will propagate to the UI.
      *
      * Typechecking is supressed because this conflicts with
      * Object.prototype.watch, which is a Gecko-only method that is recognized
      * by Closure.
      * @suppress {checkTypes}
      * @param {string} localProperty
      * @param {function(!BookmarksPageState)} valueGetter
      */
     watch: function(localProperty, valueGetter) {
-      // TODO(tsergeant): Warn if localProperty is not a defined property.
+      if (!this.getPropertyInfo(localProperty).defined) {

[tsergeant, 2017/05/02 05:09:10]

I originally TODO'd this because I thought it would be hard to deal with
behaviors...but this nifty function does it for us.

[calamity, 2017/05/02 05:35:59]

Heh.

Polymer 2.0:
Removed APIs
- element.getPropertyInfo: This api returned unexpected information some of the
time and was rarely used.

[tsergeant, 2017/05/02 05:41:56]

😔

+        console.error(
+            'No property ' + localProperty + ' defined on ' + this.is);
+      }
       this.watches_.push({
         localProperty: localProperty,
         valueGetter: valueGetter,
       });
     },
 
     /**
      * Helper to dispatch an action to the store, which will update the store
      * data and then (possibly) flow through to the UI.
      * @param {Action} action
@@ skipping 26 matching lines @@
     /** @return {!BookmarksPageState} */
     getState: function() {
       return bookmarks.Store.getInstance().data;
     },
   };
 
   return {
     StoreClient: StoreClient,
   };
 });