Fix PluginsTest.Plugins race condition and re-enable.

chrome/test/data/webui/plugins_browsertest.js

 // Copyright 2016 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 chrome://plugins
  */
 
 /** @const {string} Path to source root. */
 var ROOT_PATH = '../../../../';
 
 /**
  * Test fixture for testing async methods of cr.js.
  * @constructor
  * @extends testing.Test
  */
 function PluginsTest() {
   this.browserProxy = null;
+  this.setupFnResolver = new PromiseResolver();
 }
 
 PluginsTest.prototype = {
   __proto__: testing.Test.prototype,
 
   /** @override */
   browsePreload: 'chrome://plugins',
 
   /** @override */
   isAsync: true,
@@ skipping 51 matching lines @@
 
       saveShowDetailsToPrefs: function(expanded) {
         this.methodCalled('saveShowDetailsToPrefs', expanded);
       },
 
       setClientPage: function() {
         // Nothing to do here.
       },
     };
 
+    this.browserProxy = new TestBrowserProxy();
+
     // A function that is called from chrome://plugins to allow this test to
     // replace the real Mojo browser proxy with a fake one, before any other
     // code runs.
     window.setupFn = function() {
       return importModules([
         'mojo/public/js/bindings',
         'mojo/public/js/connection',
         'chrome/browser/ui/webui/plugins/plugins.mojom',
         'content/public/renderer/frame_interfaces',
       ]).then(function(modules) {
         var bindings = modules[0];
         var connection = modules[1];
         var pluginsMojom = modules[2];
         var frameInterfaces = modules[3];
 
         frameInterfaces.addInterfaceOverrideForTesting(
             pluginsMojom.PluginsPageHandler.name, function(handle) {
               var stub = connection.bindHandleToStub(
                   handle, pluginsMojom.PluginsPageHandler);
-              this.browserProxy = new TestBrowserProxy();
               bindings.StubBindings(stub).delegate = this.browserProxy;
             }.bind(this));
+        return this.setupFnResolver.promise;
       }.bind(this));
     }.bind(this);
   },
 };
 
-TEST_F('PluginsTest', 'DISABLED_Plugins', function() {
+TEST_F('PluginsTest', 'Plugins', function() {
   var browserProxy = this.browserProxy;
+  var setupFnResolver = this.setupFnResolver;
 
   var fakePluginData = {
     name: 'Group Name',
     description: 'description',
     version: 'version',
     update_url: 'http://update/',
     critical: true,
     enabled_mode: 'enabledByUser',
     id: 'plugin-name',
     always_allowed: false,
@@ skipping 18 matching lines @@
         ],
         enabled_mode: 'enabledByUser',
       },
     ],
   };
 
   suite('PluginTest', function() {
     var EXPECTED_PLUGINS = 2;
     suiteSetup(function() {
       browserProxy.setPluginsData([fakePluginData, fakePluginData]);
+      // Allow code being tested to proceed, now that fake data has been set up.
+      setupFnResolver.resolve();
+
       return Promise.all([
         browserProxy.whenCalled('getPluginsData'),
         browserProxy.whenCalled('getShowDetails'),
       ]);
     });
 
     teardown(function() { browserProxy.reset(); });
 
     test('PluginsUpdated', function() {
       var plugins = document.querySelectorAll('.plugin');
@@ skipping 32 matching lines @@
             return browserProxy.whenCalled('saveShowDetailsToPrefs');
           }).then(function(expanded) {
             assertFalse(Boolean(expanded));
           });
     });
   });
 
   // Run all registered tests.
   mocha.run();
 });