Update {virtual,override} to follow C++11 style in ash.

ash/host/ash_remote_window_tree_host_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_HOST_REMOTE_WINDOW_TREE_HOST_WIN_H_
 #define ASH_HOST_REMOTE_WINDOW_TREE_HOST_WIN_H_
 
 #include <windows.h>
 
 #include "ash/ash_export.h"
 #include "ash/host/ash_window_tree_host.h"
 #include "ash/host/transformer_helper.h"
 #include "ui/aura/remote_window_tree_host_win.h"
 
 namespace ash {
 
 class ASH_EXPORT AshRemoteWindowTreeHostWin
     : public AshWindowTreeHost,
       public aura::RemoteWindowTreeHostWin {
  public:
   explicit AshRemoteWindowTreeHostWin(HWND remote_hwnd);
 
  private:
-  virtual ~AshRemoteWindowTreeHostWin();
+  ~AshRemoteWindowTreeHostWin() override;
 
   // AshWindowTreeHost:
-  virtual void ToggleFullScreen() override;
-  virtual bool ConfineCursorToRootWindow() override;
-  virtual void UnConfineCursor() override;
-  virtual void SetRootWindowTransformer(
+  void ToggleFullScreen() override;
+  bool ConfineCursorToRootWindow() override;
+  void UnConfineCursor() override;
+  void SetRootWindowTransformer(
       scoped_ptr<RootWindowTransformer> transformer) override;
-  virtual gfx::Insets GetHostInsets() const override;
-  virtual aura::WindowTreeHost* AsWindowTreeHost() override;
+  gfx::Insets GetHostInsets() const override;
+  aura::WindowTreeHost* AsWindowTreeHost() override;
 
   // WindowTreeHostWin:
-  virtual gfx::Transform GetRootTransform() const override;
-  virtual void SetRootTransform(const gfx::Transform& transform) override;
-  virtual gfx::Transform GetInverseRootTransform() const override;
-  virtual void UpdateRootWindowSize(const gfx::Size& host_size) override;
+  gfx::Transform GetRootTransform() const override;
+  void SetRootTransform(const gfx::Transform& transform) override;
+  gfx::Transform GetInverseRootTransform() const override;
+  void UpdateRootWindowSize(const gfx::Size& host_size) override;
 
   TransformerHelper transformer_helper_;
 
   DISALLOW_COPY_AND_ASSIGN(AshRemoteWindowTreeHostWin);
 };
 
 }  // namespace ash
 
 #endif  // ASH_HOST_REMOTE_WINDOW_TREE_HOST_WIN_H_