Convert //ash from scoped_ptr to std::unique_ptr

ash/system/win/audio/tray_audio_win.cc

 // Copyright 2014 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.
 
 #include "ash/system/win/audio/tray_audio_win.h"
 
+#include <memory>
+
 #include "ash/system/win/audio/tray_audio_delegate_win.h"
 
 namespace ash {
 
 using system::TrayAudioDelegate;
 using system::TrayAudioDelegateWin;
 
 TrayAudioWin::TrayAudioWin(SystemTray* system_tray)
-    : TrayAudio(system_tray,
-                scoped_ptr<TrayAudioDelegate>(new TrayAudioDelegateWin())) {
-}
+    : TrayAudio(
+          system_tray,
+          std::unique_ptr<TrayAudioDelegate>(new TrayAudioDelegateWin())) {}
 
 TrayAudioWin::~TrayAudioWin() {
 }
 
 }  // namespace ash