Convert //ash from scoped_ptr to std::unique_ptr

ash/system/toast/toast_manager.h

 // Copyright 2016 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_TOAST_TOAST_MANAGER_H_
 #define ASH_SYSTEM_TOAST_TOAST_MANAGER_H_
 
+#include <memory>
 #include <queue>
 #include <string>
 
 #include "ash/ash_export.h"
 #include "ash/shell_observer.h"
 #include "ash/system/toast/toast_overlay.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/thread_checker.h"
 
 namespace ash {
@@ skipping 16 matching lines @@
 
   void ShowLatest();
   void OnDurationPassed(int toast_id);
 
   int toast_id_for_testing() const { return toast_id_; }
   ToastOverlay* GetCurrentOverlayForTesting() { return overlay_.get(); }
   void ResetToastIdForTesting() { toast_id_ = 0; }
 
   int toast_id_ = 0;
   std::queue<std::pair<std::string, uint64_t>> queue_;
-  scoped_ptr<ToastOverlay> overlay_;
+  std::unique_ptr<ToastOverlay> overlay_;
 
   base::WeakPtrFactory<ToastManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ToastManager);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_TOAST_TOAST_MANAGER_H_