Remove the most obvious dead code from message center.

ash/system/web_notification/web_notification_tray.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 ASH_SYSTEM_WEB_NOTIFICATION_WEB_NOTIFICATION_TRAY_H_
 #define ASH_SYSTEM_WEB_NOTIFICATION_WEB_NOTIFICATION_TRAY_H_
 
 #include "ash/ash_export.h"
 #include "ash/system/tray/tray_background_view.h"
 #include "ash/system/user/login_status.h"
@@ skipping 15 matching lines @@
 
 namespace views {
 class ImageButton;
 class MenuRunner;
 }
 
 namespace message_center {
 class MessageBubbleBase;
 class MessageCenter;
 class MessageCenterBubble;
-class MessagePopupBubble;
 class MessagePopupCollection;
 }
 
 namespace ash {
 
 namespace internal {
 class StatusAreaWidget;
 class WebNotificationBubbleWrapper;
 class WebNotificationButton;
 }
@@ skipping 91 matching lines @@
     return message_center_bubble_.get();
   }
 
   internal::WebNotificationBubbleWrapper* popup_bubble() const {
     return popup_bubble_.get();
   }
 
   // Testing accessors.
   bool IsPopupVisible() const;
   message_center::MessageCenterBubble* GetMessageCenterBubbleForTest();
-  message_center::MessagePopupBubble* GetPopupBubbleForTest();
 
   scoped_ptr<message_center::MessageCenterTray> message_center_tray_;
   scoped_ptr<internal::WebNotificationBubbleWrapper> message_center_bubble_;
   scoped_ptr<internal::WebNotificationBubbleWrapper> popup_bubble_;

[Jun Mukai, 2013/07/01 20:48:58]

you can remove popup_bubble_ field too

[dewittj, 2013/07/01 23:58:30]

Done.

   scoped_ptr<message_center::MessagePopupCollection> popup_collection_;
   scoped_ptr<views::MenuRunner> quiet_mode_menu_runner_;
   internal::WebNotificationButton* button_;
 
   bool show_message_center_on_unlock_;
 
   bool should_update_tray_content_;
 
   // True when the shelf auto hide behavior has to be blocked. Previously
   // this was done by checking |message_center_bubble_| but actually
   // the check can be called when creating this object, so it would cause
   // flickers of the shelf from hidden to shown. See: crbug.com/181213
   bool should_block_shelf_auto_hide_;
 
   DISALLOW_COPY_AND_ASSIGN(WebNotificationTray);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_WEB_NOTIFICATION_WEB_NOTIFICATION_TRAY_H_