Prepare SystemTray to support notifications

ash/system/tray/tray_image_item.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_TRAY_TRAY_IMAGE_ITEM_H_
 #define ASH_SYSTEM_TRAY_TRAY_IMAGE_ITEM_H_
 #pragma once
 
 #include "ash/system/tray/system_tray_item.h"
 
@@ skipping 20 matching lines @@
   virtual views::View* CreateTrayView(user::LoginStatus status) OVERRIDE;
   virtual views::View* CreateDefaultView(user::LoginStatus status) OVERRIDE;
   virtual views::View* CreateDetailedView(user::LoginStatus status) OVERRIDE;
   virtual void DestroyTrayView() OVERRIDE;
   virtual void DestroyDefaultView() OVERRIDE;
   virtual void DestroyDetailedView() OVERRIDE;
   virtual void UpdateAfterLoginStatusChange(user::LoginStatus status) OVERRIDE;
 
  private:
   int resource_id_;
-  scoped_ptr<TrayItemView> tray_view_;
+  TrayItemView* tray_view_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayImageItem);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TRAY_TRAY_IMAGE_ITEM_H_