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

ash/touch/touch_observer_hud.h

 // Copyright (c) 2012 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_TOUCH_TOUCH_OBSERVER_HUD_H_
 #define ASH_TOUCH_TOUCH_OBSERVER_HUD_H_
 
 #include "ash/ash_export.h"
 #include "ash/display/display_controller.h"
 #include "ui/events/event_handler.h"
@@ skipping 48 matching lines @@
   void OnWidgetDestroying(views::Widget* widget) override;
 
   // Overridden from gfx::DisplayObserver.
   void OnDisplayAdded(const gfx::Display& new_display) override;
   void OnDisplayRemoved(const gfx::Display& old_display) override;
   void OnDisplayMetricsChanged(const gfx::Display& display,
                                uint32_t metrics) override;
 
 #if defined(OS_CHROMEOS)
   // Overriden from ui::DisplayConfigurator::Observer.
-  virtual void OnDisplayModeChanged(
+  void OnDisplayModeChanged(
       const ui::DisplayConfigurator::DisplayStateList& outputs) override;
 #endif  // defined(OS_CHROMEOS)
 
   // Overriden form DisplayController::Observer.
   void OnDisplaysInitialized() override;
   void OnDisplayConfigurationChanging() override;
   void OnDisplayConfigurationChanged() override;
 
  private:
   friend class TouchHudTestBase;
 
   const int64 display_id_;
   aura::Window* root_window_;
 
   views::Widget* widget_;
 
   DISALLOW_COPY_AND_ASSIGN(TouchObserverHUD);
 };
 
 }  // namespace ash
 
 #endif  // ASH_TOUCH_TOUCH_OBSERVER_HUD_H_