Convert //ash from scoped_ptr to std::unique_ptr

ash/system/chromeos/network/tray_vpn.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_CHROMEOS_NETWORK_TRAY_VPN_H
 #define ASH_SYSTEM_CHROMEOS_NETWORK_TRAY_VPN_H
 
+#include <memory>
+
 #include "ash/system/chromeos/network/tray_network_state_observer.h"
 #include "ash/system/tray/system_tray_item.h"
 #include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
 
 namespace ash {
 class TrayNetworkStateObserver;
 
 namespace tray {
 class NetworkDetailedView;
 class VpnDefaultView;
 class VpnDetailedView;
 }
 
@@ skipping 12 matching lines @@
   void DestroyDetailedView() override;
   void UpdateAfterLoginStatusChange(user::LoginStatus status) override;
   void UpdateAfterShelfAlignmentChange(ShelfAlignment alignment) override;
 
   // TrayNetworkStateObserver::Delegate
   void NetworkStateChanged() override;
 
  private:
   tray::VpnDefaultView* default_;
   tray::NetworkDetailedView* detailed_;
-  scoped_ptr<TrayNetworkStateObserver> network_state_observer_;
+  std::unique_ptr<TrayNetworkStateObserver> network_state_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayVPN);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_CHROMEOS_NETWORK_TRAY_VPN_H