Fix a bug of black area on window close

chrome/browser/resources/feedback/js/topbar_handlers.js

 // Copyright 2013 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.
 
 /**
  * Setup handlers for the minimize and close topbar buttons.
  */
 function initializeHandlers() {
   // If this dialog is using system window controls, these elements aren't
   // needed at all.
   if (window.feedbackInfo.useSystemWindowFrame) {
     $('minimize-button').hidden = true;
     $('close-button').hidden = true;
     return;
   }
   $('minimize-button').addEventListener('click', function(e) {
     e.preventDefault();
     chrome.app.window.current().minimize();
   });
 
   $('minimize-button').addEventListener('mousedown', function(e) {
     e.preventDefault();
   });
 
   $('close-button').addEventListener('click', function() {
-    window.close();
+    scheduleWindowClose();
   });
 
   $('close-button').addEventListener('mousedown', function(e) {
     e.preventDefault();
   });
 }
 
 window.addEventListener('DOMContentLoaded', initializeHandlers);