Standardize usage of virtual/override/final in chrome/

chrome/test/remoting/page_load_notification_observer.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 CHROME_TEST_REMOTING_PAGE_LOAD_NOTIFICATION_OBSERVER_H_
 #define CHROME_TEST_REMOTING_PAGE_LOAD_NOTIFICATION_OBSERVER_H_
 
 #include "content/public/test/test_utils.h"
 #include "url/gurl.h"
 
 namespace remoting {
 
 // A PageLoadNotificationObserver allows code to wait until a give URL is loaded
 // in any tab in any browser window, i.e. NotificationService::AllSources().
 // This simple pattern is not easy to implement using
 // WindowedNotificationObserver because we need to bind the observer object
 // in the callback but we also need to provide the callback when constructing
 // the observer object.
 class PageLoadNotificationObserver
     : public content::WindowedNotificationObserver {
  public:
   explicit PageLoadNotificationObserver(const GURL& target);
 
-  virtual ~PageLoadNotificationObserver();
+  ~PageLoadNotificationObserver() override;
 
  private:
   bool IsTargetLoaded();
   GURL target_;
   DISALLOW_COPY_AND_ASSIGN(PageLoadNotificationObserver);
 };
 
 }  // namespace remoting
 
 #endif  // CHROME_TEST_REMOTING_PAGE_LOAD_NOTIFICATION_OBSERVER_H_