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

chrome/browser/ui/screen_capture_notification_ui_stub.cc

 // 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.
 
 #include "chrome/browser/ui/screen_capture_notification_ui.h"
 
 #include "base/logging.h"
 
 // Stub implementation of the ScreenCaptureNotificationUI interface.
 class ScreenCaptureNotificationUIStub : public ScreenCaptureNotificationUI {
  public:
   ScreenCaptureNotificationUIStub() {}
-  virtual ~ScreenCaptureNotificationUIStub() {}
+  ~ScreenCaptureNotificationUIStub() override {}
 
-  virtual gfx::NativeViewId OnStarted(const base::Closure& stop_callback)
-      override {
+  gfx::NativeViewId OnStarted(const base::Closure& stop_callback) override {
     NOTIMPLEMENTED();
     return 0;
   }
 };
 
 // static
 scoped_ptr<ScreenCaptureNotificationUI> ScreenCaptureNotificationUI::Create(
     const base::string16& title) {
   return scoped_ptr<ScreenCaptureNotificationUI>(
       new ScreenCaptureNotificationUIStub());
 }