MD Bookmarks: Support policies for disabling bookmark editing

chrome/test/data/webui/md_bookmarks/md_bookmarks_focus_test.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 Tests for MD Bookmarks which are run as interactive ui tests.
  * Should be used for tests which care about focus.
  */
 
 var ROOT_PATH = '../../../../../';
@@ skipping 168 matching lines @@
 
       document.body.style.direction = 'ltr';
     });
 
     test('keyboard commands are passed to command manager', function() {
       var commandManager = new TestCommandManager();
       document.body.appendChild(commandManager);
       chrome.bookmarkManagerPrivate.removeTrees = function() {}
 
       store.data.selection.items = new Set(['3', '4']);
+      store.data.selectedFolder = '2';
       store.notifyObservers();
 
-      getFolderNode('1').$.container.focus();
-      keydown('1', 'delete');
+      getFolderNode('2').$.container.focus();
+      keydown('2', 'delete');
 
-      commandManager.assertLastCommand(Command.DELETE, ['1']);
+      commandManager.assertLastCommand(Command.DELETE, ['2']);
     });
   });
 
   suite('<bookmarks-list>', function() {
     var list;
     var store;
     var items;
     var multiKey = cr.isMac ? 'meta' : 'ctrl';
 
     function keydown(item, key, modifiers) {
@@ skipping 184 matching lines @@
       var button = items[0].$$('.more-vert-button');
       button.focus();
       keydown(button, 'Enter');
 
       assertEquals(button, items[0].root.activeElement);
     });
   });
 
   mocha.run();
 });