Add promise_resolver.js to PolymerTest libraries

chrome/test/data/webui/polymer_browser_test_base.js

 // Copyright 2015 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 Framework for running JavaScript tests of Polymer elements.
  */
 
 /**
  * Test fixture for Polymer element testing.
@@ skipping 20 matching lines @@
    */
   isAsync: true,
 
   /**
    * Files that need not be compiled. Should be overridden to use correct
    * relative paths with PolymerTest.getLibraries.
    * @override
    */
   extraLibraries: [
     'ui/webui/resources/js/cr.js',
+    'ui/webui/resources/js/promise_resolver.js',
     'third_party/mocha/mocha.js',
     'chrome/test/data/webui/mocha_adapter.js',
   ],
 
   /** Time when preLoad starts, i.e. before the browsePreload page is loaded. */
   preloadTime: 0,
 
   /** Time when test run starts. */
   runTime: 0,
 
@@ skipping 122 matching lines @@
  */
 PolymerTest.getLibraries = function(basePath) {
   // Ensure basePath ends in '/'.
   if (basePath.length && basePath[basePath.length - 1] != '/')
     basePath += '/';
 
   return PolymerTest.prototype.extraLibraries.map(function(library) {
     return basePath + library;
   });
 };