Convert //ash from scoped_ptr to std::unique_ptr

ash/host/ash_window_tree_host_platform.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_HOST_ASH_WINDOW_TREE_HOST_PLATFORM_H_
 #define ASH_HOST_ASH_WINDOW_TREE_HOST_PLATFORM_H_
 
+#include <memory>
+
 #include "ash/ash_export.h"
 #include "ash/host/ash_window_tree_host.h"
 #include "ash/host/transformer_helper.h"
 #include "ui/aura/window_tree_host_platform.h"
 
 namespace ash {
 
 class ASH_EXPORT AshWindowTreeHostPlatform
     : public AshWindowTreeHost,
       public aura::WindowTreeHostPlatform {
  public:
   explicit AshWindowTreeHostPlatform(const gfx::Rect& initial_bounds);
   ~AshWindowTreeHostPlatform() override;
 
  protected:
   AshWindowTreeHostPlatform();
 
   // AshWindowTreeHost:
   void ToggleFullScreen() override;
   bool ConfineCursorToRootWindow() override;
   void UnConfineCursor() override;
   void SetRootWindowTransformer(
-      scoped_ptr<RootWindowTransformer> transformer) override;
+      std::unique_ptr<RootWindowTransformer> transformer) override;
   gfx::Insets GetHostInsets() const override;
   aura::WindowTreeHost* AsWindowTreeHost() override;
   void PrepareForShutdown() override;
   void SetRootTransform(const gfx::Transform& transform) override;
   gfx::Transform GetRootTransform() const override;
   gfx::Transform GetInverseRootTransform() const override;
   void UpdateRootWindowSize(const gfx::Size& host_size) override;
   void OnCursorVisibilityChangedNative(bool show) override;
   void SetBounds(const gfx::Rect& bounds) override;
   void DispatchEvent(ui::Event* event) override;
 
   // ui::internal::InputMethodDelegate:
   ui::EventDispatchDetails DispatchKeyEventPostIME(
       ui::KeyEvent* event) override;
 
  private:
   // Temporarily disable the tap-to-click feature. Used on CrOS.
   void SetTapToClickPaused(bool state);
 
   TransformerHelper transformer_helper_;
 
   DISALLOW_COPY_AND_ASSIGN(AshWindowTreeHostPlatform);
 };
 
 }  // namespace ash
 
 #endif  // ASH_HOST_ASH_WINDOW_TREE_HOST_PLATFORM_H_