Convert //ash from scoped_ptr to std::unique_ptr

ash/system/win/audio/tray_audio_win.h

 // 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.
 
 #ifndef ASH_SYSTEM_WIN_AUDIO_TRAY_AUDIO_WIN_H_
 #define ASH_SYSTEM_WIN_AUDIO_TRAY_AUDIO_WIN_H_
 
 #include "ash/ash_export.h"
 #include "ash/system/audio/tray_audio.h"
 #include "base/macros.h"
-#include "base/memory/scoped_ptr.h"
 
 namespace ash {
 
 class TrayAudioWin : public TrayAudio {
  public:
   explicit TrayAudioWin(SystemTray* system_tray);
   ~TrayAudioWin() override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(TrayAudioWin);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_WIN_AUDIO_TRAY_AUDIO_WIN_H_