MD Bookmarks: Support policies for disabling bookmark editing

chrome/test/data/webui/md_bookmarks/policy_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.
 
-suite('Incognito policy', function() {
+suite('Bookmarks policies', function() {
   var store;
   var app;
 
   setup(function() {
     store = new bookmarks.TestStore({
       nodes: testTree(createFolder(
           '1',
           [
             createItem('11'),
           ])),
       selectedFolder: '1',
     });
     store.setReducersEnabled(true);
     store.expectAction('set-incognito-availability');
+    store.expectAction('set-can-edit');
     store.replaceSingleton();
 
     app = document.createElement('bookmarks-app');
     replaceBody(app);
   });
 
-  test('updates when changed by the browser', function() {
+  test('incognito availability updates when changed', function() {
     var commandManager = bookmarks.CommandManager.getInstance();
     // Incognito is disabled during testGenPreamble(). Wait for the front-end to
     // load the config.
     return store.waitForAction('set-incognito-availability').then(action => {
       assertEquals(IncognitoAvailability.DISABLED,
           store.data.prefs.incognitoAvailability);
       assertFalse(
           commandManager.canExecute(Command.OPEN_INCOGNITO, new Set(['11'])));
 
       return cr.sendWithPromise(
           'testSetIncognito', IncognitoAvailability.ENABLED);
     }).then(() => {
       assertEquals(IncognitoAvailability.ENABLED,
           store.data.prefs.incognitoAvailability);
       assertTrue(
           commandManager.canExecute(Command.OPEN_INCOGNITO, new Set(['11'])));
     });
   });
+
+  test('canEdit updates when changed', function() {
+    var commandManager = bookmarks.CommandManager.getInstance();
+    return store.waitForAction('set-can-edit').then(action => {
+      assertFalse(store.data.prefs.canEdit);
+      assertFalse(commandManager.canExecute(Command.DELETE, new Set(['11'])));
+
+      return cr.sendWithPromise('testSetCanEdit', true);
+    }).then(() => {
+      assertTrue(store.data.prefs.canEdit);
+      assertTrue(commandManager.canExecute(Command.DELETE, new Set(['11'])));
+    });
+  });
 });