Makes the response to CheckNotificationPermission asynchronous.

content/public/browser/content_browser_client.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_
 #define CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_
 
 #include <map>
 #include <string>
 #include <utility>
@@ skipping 411 matching lines @@
   virtual MediaObserver* GetMediaObserver();
 
   // Asks permission to show desktop notifications.
   virtual void RequestDesktopNotificationPermission(
       const GURL& source_origin,
       int callback_context,
       int render_process_id,
       int render_view_id) {}
 
   // Checks if the given page has permission to show desktop notifications.
-  // This is called on the IO thread.
+  // This is called on the UI thread.
   virtual WebKit::WebNotificationPresenter::Permission
       CheckDesktopNotificationPermission(
           const GURL& source_url,
           ResourceContext* context,
           int render_process_id);
 
   // Show a desktop notification.  If |worker| is true, the request came from an
   // HTML5 web worker, otherwise, it came from a renderer.
   virtual void ShowDesktopNotification(
       const ShowDesktopNotificationHostMsgParams& params,
@@ skipping 153 matching lines @@
   // This is called on a worker thread.
   virtual
       crypto::CryptoModuleBlockingPasswordDelegate* GetCryptoPasswordDelegate(
           const GURL& url);
 #endif
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_CONTENT_BROWSER_CLIENT_H_