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

ash/system/chromeos/power/tray_power.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_SYSTEM_CHROMEOS_POWER_TRAY_POWER_H_
 #define ASH_SYSTEM_CHROMEOS_POWER_TRAY_POWER_H_
 
 #include "ash/system/chromeos/power/power_status.h"
 #include "ash/system/tray/system_tray_item.h"
 
@@ skipping 33 matching lines @@
   static const int kLowPowerMinutes;
   static const int kNoWarningMinutes;
 
   // Percentage-based notification thresholds when using a low-power charger.
   static const int kCriticalPercentage;
   static const int kLowPowerPercentage;
   static const int kNoWarningPercentage;
 
   TrayPower(SystemTray* system_tray,
             message_center::MessageCenter* message_center);
-  virtual ~TrayPower();
+  ~TrayPower() override;
 
  private:
   friend class TrayPowerTest;
 
   // This enum is used for histogram. The existing values should not be removed,
   // and the new values should be added just before CHARGER_TYPE_COUNT.
   enum ChargerType{
     UNKNOWN_CHARGER,
     MAINS_CHARGER,
     USB_CHARGER,
     UNCONFIRMED_SPRING_CHARGER,
     SAFE_SPRING_CHARGER,
     CHARGER_TYPE_COUNT,
   };
 
   // Overridden from SystemTrayItem.
-  virtual views::View* CreateTrayView(user::LoginStatus status) override;
-  virtual views::View* CreateDefaultView(user::LoginStatus status) override;
-  virtual views::View* CreateNotificationView(
-      user::LoginStatus status) override;
-  virtual void DestroyTrayView() override;
-  virtual void DestroyDefaultView() override;
-  virtual void DestroyNotificationView() override;
-  virtual void UpdateAfterLoginStatusChange(user::LoginStatus status) override;
-  virtual void UpdateAfterShelfAlignmentChange(
-      ShelfAlignment alignment) override;
+  views::View* CreateTrayView(user::LoginStatus status) override;
+  views::View* CreateDefaultView(user::LoginStatus status) override;
+  views::View* CreateNotificationView(user::LoginStatus status) override;
+  void DestroyTrayView() override;
+  void DestroyDefaultView() override;
+  void DestroyNotificationView() override;
+  void UpdateAfterLoginStatusChange(user::LoginStatus status) override;
+  void UpdateAfterShelfAlignmentChange(ShelfAlignment alignment) override;
 
   // Overridden from PowerStatus::Observer.
-  virtual void OnPowerStatusChanged() override;
+  void OnPowerStatusChanged() override;
 
   // Show a notification that a low-power USB charger has been connected.
   // Returns true if a notification was shown or explicitly hidden.
   bool MaybeShowUsbChargerNotification();
 
   // Sets |notification_state_|. Returns true if a notification should be shown.
   bool UpdateNotificationState();
   bool UpdateNotificationStateForRemainingTime();
   bool UpdateNotificationStateForRemainingPercentage();
 
   message_center::MessageCenter* message_center_;  // Not owned.
   tray::PowerTrayView* power_tray_;
   tray::PowerNotificationView* notification_view_;
   NotificationState notification_state_;
 
   // Was a USB charger connected the last time OnPowerStatusChanged() was
   // called?
   bool usb_charger_was_connected_;
 
   // Was line power connected the last time onPowerStatusChanged() was called?
   bool line_power_was_connected_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayPower);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_CHROMEOS_POWER_TRAY_POWER_H_