Removes some dead code

ash/host/ash_window_tree_host_win.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_WIN_H_
-#define ASH_HOST_ASH_WINDOW_TREE_HOST_WIN_H_
-
-#include "ash/host/ash_window_tree_host_platform.h"
-
-namespace ash {
-
-class AshWindowTreeHostWin : public AshWindowTreeHostPlatform {
- public:
-  explicit AshWindowTreeHostWin(const gfx::Rect& initial_bounds);
-  ~AshWindowTreeHostWin() override;
-
- private:
-  // AshWindowTreeHost:
-  void ToggleFullScreen() override;
-
-  // WindowTreeHost:
-  void SetBoundsInPixels(const gfx::Rect& bounds) override;
-
-  bool fullscreen_;
-  RECT saved_window_rect_;
-  DWORD saved_window_style_;
-  DWORD saved_window_ex_style_;
-
-  DISALLOW_COPY_AND_ASSIGN(AshWindowTreeHostWin);
-};
-
-}  // namespace ash
-
-#endif  // ASH_HOST_ASH_WINDOW_TREE_HOST_WIN_H_