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

ash/wm/power_button_controller.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_WM_POWER_BUTTON_CONTROLLER_H_
 #define ASH_WM_POWER_BUTTON_CONTROLLER_H_
 
 #include "ash/accelerators/accelerator_controller.h"
 #include "ash/accelerators/accelerator_table.h"
 #include "ash/ash_export.h"
@@ skipping 50 matching lines @@
 
   // Called when the power or lock buttons are pressed or released.
   void OnPowerButtonEvent(bool down, const base::TimeTicks& timestamp);
   void OnLockButtonEvent(bool down, const base::TimeTicks& timestamp);
 
   // ui::EventHandler:
   void OnKeyEvent(ui::KeyEvent* event) override;
 
 #if defined(OS_CHROMEOS)
   // Overriden from ui::DisplayConfigurator::Observer:
-  virtual void OnDisplayModeChanged(
+  void OnDisplayModeChanged(
       const ui::DisplayConfigurator::DisplayStateList& outputs) override;
 #endif
 
  private:
   friend class test::PowerButtonControllerTest;
 
   // Are the power or lock buttons currently held?
   bool power_button_down_;
   bool lock_button_down_;
 
@@ skipping 16 matching lines @@
   bool enable_quick_lock_;
 
   LockStateController* controller_;  // Not owned.
 
   DISALLOW_COPY_AND_ASSIGN(PowerButtonController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_POWER_BUTTON_CONTROLLER_H_