MD User Manager: Fixes flaky tests

chrome/test/data/webui/md_user_manager/create_profile_tests.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.
 
 cr.define('user_manager.create_profile_tests', function() {
   /** @return {!CreateProfileElement} */
   function createElement() {
-    PolymerTest.clearBody();
     var createProfileElement = document.createElement('create-profile');
     document.body.appendChild(createProfileElement);
     return createProfileElement;
   }
 
   function registerTests() {
     /** @type {?TestProfileBrowserProxy} */
     var browserProxy = null;
 
     /** @type {?CreateProfileElement} */
@@ skipping 14 matching lines @@
                                                   onCurrentDevice: true},
                                                  {name: 'existing name 2',
                                                   onCurrentDevice: false}]);
 
         createProfileElement = createElement();
 
         // Make sure DOM is up to date.
         Polymer.dom.flush();
       });
 
-      teardown(function() { createProfileElement.remove(); });
+      teardown(function(done) {
+        createProfileElement.remove();
+        // Allow asynchronous tasks to finish.
+        setTimeout(done);
+      });
 
       test('Handles available profile icons', function() {
         return browserProxy.whenCalled('getAvailableIcons').then(function() {
           assertEquals('icon1.png', createProfileElement.profileIconUrl_);
         });
       });
 
       test('Handles signed in users', function() {
         return browserProxy.whenCalled('getSignedInUsers').then(function() {
           assertEquals(1, createProfileElement.signedInUsers_.length);
@@ skipping 314 matching lines @@
         signin.ProfileBrowserProxyImpl.instance_ = browserProxy;
 
         browserProxy.setIcons([{url: 'icon1.png', label: 'icon1'}]);
 
         createProfileElement = createElement();
 
         // Make sure DOM is up to date.
         Polymer.dom.flush();
       });
 
-      teardown(function() { createProfileElement.remove(); });
+      teardown(function(done) {
+        createProfileElement.remove();
+        // Allow asynchronous tasks to finish.
+        setTimeout(done);
+      });
 
       test('Handles no signed in users', function() {
         return browserProxy.whenCalled('getSignedInUsers').then(function() {
           assertEquals(0, createProfileElement.signedInUsers_.length);
 
           // Simulate checking the checkbox.
           MockInteractions.tap(createProfileElement.$$('paper-checkbox'));
           Polymer.dom.flush();
 
           // The dropdown menu is not visible when there are no signed in users.
           assertFalse(!!createProfileElement.$$('paper-dropdown-menu'));
 
           // Instead a message containing a link to the Help Center on how
           // to sign in to Chrome is displaying.
           assertTrue(!!createProfileElement.$$('#sign-in-to-chrome'));
         });
       });
 
       test('Create button is disabled', function() {
         assertTrue(createProfileElement.$.save.disabled);
       });
     });
   }
 
   return {
     registerTests: registerTests,
   };
 });