md-settings: Fix back navigation from /resetProfileSettings.

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 188 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;
   });
 };
+
+/*
+ * Waits for queued up tasks to finish before proceeding. Inspired by:
+ * https://github.com/Polymer/web-component-tester/blob/master/browser/environment/helpers.js#L97
+ */
+PolymerTest.flushTasks = function() {
+  Polymer.dom.flush();
+  // Promises have microtask timing, so we use setTimeout to explicity force a
+  // new task.
+  return new Promise(function(resolve, reject) {
+    window.setTimeout(resolve, 0);
+  });
+};