[Media Router WebUI] Run afterNextRender() before tests using media-router-container.

chrome/test/data/webui/media_router/media_router_header_tests.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 Suite of tests for media-router-header. */
 cr.define('media_router_header', function() {
   function registerTests() {
     suite('MediaRouterHeader', function() {
       /**
+       * Media Router Container created before each test.
+       * @type {?MediaRouterContainer}
+       */
+      var container;
+
+      /**
        * Media Router Header created before each test.
        * @type {MediaRouterHeader}
        */
       var header;
 
       /**
        * The list of elements to check for visibility.
        * @const {!Array<string>}
        */
       var hiddenCheckElementIdList = [
@@ skipping 45 matching lines @@
             'media_router_container.html');
       });
 
       // Initialize an media-router-header before each test.
       setup(function(done) {
         PolymerTest.clearBody();
         container = document.createElement('media-router-container');
         document.body.appendChild(container);
         header = container.$['container-header'];
 
-        // Allow for the media router header to be created and attached.
-        setTimeout(done);
+        // Allow for the media router container to be created, attached, and
+        // listeners registered in an afterNextRender() call.
+        Polymer.RenderStatus.afterNextRender(this, done);
       });
 
       // Tests for 'close-dialog' event firing when the close button is
       // clicked.
       test('close button click', function(done) {
         header.addEventListener('close-dialog', function(data) {
           assertFalse(data.detail.pressEscToClose);
           done();
         });
         MockInteractions.tap(header.$['close-button']);
@@ skipping 174 matching lines @@
           done();
         });
       });
     });
   }
 
   return {
     registerTests: registerTests,
   };
 });