ash: Cleanup class/struct forward declarations

ash/common/system/user/tray_user.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_COMMON_SYSTEM_USER_TRAY_USER_H_
 #define ASH_COMMON_SYSTEM_USER_TRAY_USER_H_
 
 #include "ash/ash_export.h"
 #include "ash/common/session/session_types.h"
 #include "ash/common/system/tray/system_tray_item.h"
 #include "ash/common/system/user/user_observer.h"
 #include "base/macros.h"
 
 namespace gfx {
 class Rect;
 class Size;
 }
 
 namespace views {
-class ImageView;
 class Label;
 }
 
 namespace ash {
 
 namespace tray {
 class RoundedImageView;
 class UserView;
 }
 
@@ skipping 56 matching lines @@
   views::View* layout_view_;
   tray::RoundedImageView* avatar_;
   views::Label* label_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayUser);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_USER_TRAY_USER_H_