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

ash/system/chromeos/brightness/tray_brightness.h

 // Copyright 2013 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_SYSTEM_CHROMEOS_BRIGHTNESS_TRAY_BRIGHTNESS_H_
 #define ASH_SYSTEM_CHROMEOS_BRIGHTNESS_TRAY_BRIGHTNESS_H_
 
 #include "ash/system/tray/system_tray_item.h"
 #include "base/compiler_specific.h"
 #include "base/memory/weak_ptr.h"
 #include "chromeos/dbus/power_manager_client.h"
 
 namespace ash {
 namespace tray {
 class BrightnessView;
 }
 
 class ASH_EXPORT TrayBrightness
     : public SystemTrayItem,
       public chromeos::PowerManagerClient::Observer {
  public:
   explicit TrayBrightness(SystemTray* system_tray);
-  virtual ~TrayBrightness();
+  ~TrayBrightness() override;
 
  private:
   friend class TrayBrightnessTest;
 
   // Sends a request to get the current screen brightness so |current_percent_|
   // can be initialized.
   void GetInitialBrightness();
 
   // Updates |current_percent_| with the initial brightness requested by
   // GetInitialBrightness(), if we haven't seen the brightness already in the
   // meantime.
   void HandleInitialBrightness(double percent);
 
   // Overridden from SystemTrayItem.
-  virtual views::View* CreateTrayView(user::LoginStatus status) override;
-  virtual views::View* CreateDefaultView(user::LoginStatus status) override;
-  virtual views::View* CreateDetailedView(user::LoginStatus status) override;
-  virtual void DestroyTrayView() override;
-  virtual void DestroyDefaultView() override;
-  virtual void DestroyDetailedView() override;
-  virtual void UpdateAfterLoginStatusChange(user::LoginStatus status) override;
-  virtual bool ShouldHideArrow() const override;
-  virtual bool ShouldShowShelf() const override;
+  views::View* CreateTrayView(user::LoginStatus status) override;
+  views::View* CreateDefaultView(user::LoginStatus status) override;
+  views::View* CreateDetailedView(user::LoginStatus status) override;
+  void DestroyTrayView() override;
+  void DestroyDefaultView() override;
+  void DestroyDetailedView() override;
+  void UpdateAfterLoginStatusChange(user::LoginStatus status) override;
+  bool ShouldHideArrow() const override;
+  bool ShouldShowShelf() const override;
 
   // Overriden from PowerManagerClient::Observer.
-  virtual void BrightnessChanged(int level, bool user_initiated) override;
+  void BrightnessChanged(int level, bool user_initiated) override;
 
   void HandleBrightnessChanged(double percent, bool user_initiated);
 
   tray::BrightnessView* brightness_view_;
 
   // Brightness level in the range [0.0, 100.0] that we've heard about most
   // recently.
   double current_percent_;
 
   // Has |current_percent_| been initialized?
   bool got_current_percent_;
 
   base::WeakPtrFactory<TrayBrightness> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayBrightness);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_CHROMEOS_BRIGHTNESS_TRAY_BRIGHTNESS_H_