MD Bookmarks: Update a couple of TODOs

chrome/test/data/webui/md_bookmarks/test_store.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.
 
 suiteSetup(function() {
   cr.define('bookmarks', function() {
     var TestStore = function(data) {
       bookmarks.Store.call(this);
       this.data_ = Object.assign(bookmarks.util.createEmptyState(), data);
       this.initialized_ = true;
@@ skipping 34 matching lines @@
       setReducersEnabled: function(enabled) {
         this.enableReducers_ = enabled;
       },
 
       reduce_: function(action) {
         this.lastAction_ = action;
         if (this.enableReducers_)
           bookmarks.Store.prototype.reduce_.call(this, action);
       },
 
+      /**
+       * Notifies UI elements that the store data has changed. When reducers are
+       * disabled, tests are responsible for manually changing the data to make
+       * UI elements update correctly (eg, tests must replace the whole list
+       * when changing a single element).

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

It's been long enough to convince me that we don't need any sort of deep clone
behavior here: just making sure that tests update the right things is
sufficient.

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

Agreed. I don't foresee any other major data members that will have these
problems.

+       */
       notifyObservers: function() {
-        // TODO(tsergeant): Revisit how state modifications work in UI tests.
-        // We don't want tests to worry about modifying the whole state tree.
-        // Instead, we could perform a deep clone in here to ensure that every
-        // StoreClient is updated.
         this.notifyObservers_(this.data);
       },
 
       // Call in order to accept data from an init call to the TestStore once.
       acceptInitOnce: function() {
         this.acceptInit_ = true;
         this.initialized_ = false;
       },
     };
 
     return {
       TestStore: TestStore,
     };
   });
 });