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

ash/system/chromeos/session/logout_confirmation_controller.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_SYSTEM_CHROMEOS_SESSION_LOGOUT_CONFIRMATION_CONTROLLER_H_
 #define ASH_SYSTEM_CHROMEOS_SESSION_LOGOUT_CONFIRMATION_CONTROLLER_H_
 
 #include "ash/ash_export.h"
 #include "ash/shell_observer.h"
 #include "base/basictypes.h"
@@ skipping 13 matching lines @@
 // This class shows a dialog asking the user to confirm or deny logout and
 // terminates the session if the user either confirms or allows the countdown
 // shown in the dialog to expire.
 // It is guaranteed that no more than one confirmation dialog will be visible at
 // any given time. If there are multiple requests to show a confirmation dialog
 // at the same time, the dialog whose countdown expires first is shown.
 class ASH_EXPORT LogoutConfirmationController : public ShellObserver {
  public:
   // The |logout_closure| must be safe to call as long as |this| is alive.
   explicit LogoutConfirmationController(const base::Closure& logout_closure);
-  virtual ~LogoutConfirmationController();
+  ~LogoutConfirmationController() override;
 
   base::TickClock* clock() const { return clock_.get(); }
 
   // Shows a LogoutConfirmationDialog. If a confirmation dialog is already being
   // shown, it is closed and a new one opened if |logout_time| is earlier than
   // the current dialog's |logout_time_|.
   void ConfirmLogout(base::TimeTicks logout_time);
 
   void SetClockForTesting(scoped_ptr<base::TickClock> clock);
 
   // ShellObserver:
-  virtual void OnLockStateChanged(bool locked) override;
+  void OnLockStateChanged(bool locked) override;
 
   // Called by the |dialog_| when the user confirms logout.
   void OnLogoutConfirmed();
 
   // Called by the |dialog_| when it is closed.
   void OnDialogClosed();
 
   LogoutConfirmationDialog* dialog_for_testing() const { return dialog_; }
 
  private:
   scoped_ptr<base::TickClock> clock_;
   base::Closure logout_closure_;
 
   base::TimeTicks logout_time_;
   LogoutConfirmationDialog* dialog_;  // Owned by the Views hierarchy.
   base::Timer logout_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(LogoutConfirmationController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_CHROMEOS_SESSION_LOGOUT_CONFIRMATION_CONTROLLER_H_