Remove unnecessary, left over Polymer.dom.flush() from appearance tests

chrome/test/data/webui/settings/appearance_page_test.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 Runs polymer appearance font settings elements. */
 
 cr.define('settings_appearance', function() {
   /**
    * A test version of AppearanceBrowserProxy.
    *
@@ skipping 125 matching lines @@
 
       test('useDefaultTheme', function() {
         var button = appearancePage.$$('#useDefault');
         assertTrue(!!button);
         MockInteractions.tap(button);
         return appearanceBrowserProxy.whenCalled('useDefaultTheme');
       });
 
       if (cr.isLinux && !cr.isChromeOS) {
         test('useSystemTheme', function() {
-          Polymer.dom.flush();
-
           var button = appearancePage.$$('#useSystem');
           assertTrue(!!button);
           MockInteractions.tap(button);
           return appearanceBrowserProxy.whenCalled('useSystemTheme');
         });
       }
     });
   }
 
   function registerAppearanceFontSettingsBrowserTest() {
@@ skipping 30 matching lines @@
     });
   }
 
   return {
     registerTests: function() {
       registerAppearanceFontSettingsBrowserTest();
       registerAppearanceSettingsBrowserTest();
     },
   };
 });