Declaring the weak_ptr_factory in proper order.

ash/system/chromeos/brightness/tray_brightness.h

 // Copyright 2013 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_CHROMEOS_BRIGHTNESS_TRAY_BRIGHTNESS_H_
 #define ASH_SYSTEM_CHROMEOS_BRIGHTNESS_TRAY_BRIGHTNESS_H_
 
 #include "ash/system/tray/system_tray_item.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 32 matching lines @@
   virtual void DestroyDetailedView() OVERRIDE;
   virtual void UpdateAfterLoginStatusChange(user::LoginStatus status) OVERRIDE;
   virtual bool ShouldHideArrow() const OVERRIDE;
   virtual bool ShouldShowShelf() const OVERRIDE;
 
   // Overriden from PowerManagerClient::Observer.
   virtual void BrightnessChanged(int level, bool user_initiated) OVERRIDE;
 
   void HandleBrightnessChanged(double percent, bool user_initiated);
 
-  base::WeakPtrFactory<TrayBrightness> weak_ptr_factory_;
-
   tray::BrightnessView* brightness_view_;
 
   // Brightness level in the range [0.0, 100.0] that we've heard about most
   // recently.
   double current_percent_;
 
   // Has |current_percent_| been initialized?
   bool got_current_percent_;
 
+  base::WeakPtrFactory<TrayBrightness> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(TrayBrightness);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_CHROMEOS_BRIGHTNESS_TRAY_BRIGHTNESS_H_