Convert //ash from scoped_ptr to std::unique_ptr

ash/system/chromeos/power/battery_notification.h

 // Copyright 2015 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_POWER_BATTERY_NOTIFICATION_H_
 #define ASH_SYSTEM_CHROMEOS_POWER_BATTERY_NOTIFICATION_H_
 
 #include "ash/ash_export.h"
 #include "ash/system/chromeos/power/tray_power.h"
 #include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
 
 namespace message_center {
 class MessageCenter;
 }
 
 namespace ash {
 
 // Class for showing and hiding a MessageCenter low battery notification.
 class ASH_EXPORT BatteryNotification {
  public:
   BatteryNotification(message_center::MessageCenter* message_center,
                       TrayPower::NotificationState notification_state);
   ~BatteryNotification();
 
   // Updates the notification if it still exists.
   void Update(TrayPower::NotificationState notification_state);
 
  private:
   message_center::MessageCenter* message_center_;
 
   DISALLOW_COPY_AND_ASSIGN(BatteryNotification);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_CHROMEOS_POWER_BATTERY_NOTIFICATION_H_