Uses WeakPtrFactory instead of base::Unretained.

ash/system/ime/tray_ime.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_IME_TRAY_IME_H_
 #define ASH_SYSTEM_IME_TRAY_IME_H_
 
 #include "ash/system/ime/ime_observer.h"
 #include "ash/system/tray/system_tray_item.h"
+#include "base/memory/weak_ptr.h"
 
 namespace views {
 class Label;
 }
 
 namespace ash {
 
 struct IMEInfo;
 
 namespace internal {
@@ skipping 34 matching lines @@
 
   // Overridden from IMEObserver.
   virtual void OnIMERefresh(bool show_message) OVERRIDE;
 
   TrayItemView* tray_label_;
   tray::IMEDefaultView* default_;
   tray::IMEDetailedView* detailed_;
 
   bool message_shown_;
 
+  base::WeakPtrFactory<TrayIME> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(TrayIME);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_IME_TRAY_IME_H_