Standardize usage of virtual/override/final in chrome/browser/

chrome/browser/thumbnails/thumbnail_tab_helper.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 CHROME_BROWSER_THUMBNAILS_THUMBNAIL_TAB_HELPER_H_
 #define CHROME_BROWSER_THUMBNAILS_THUMBNAIL_TAB_HELPER_H_
 
 #include "base/basictypes.h"
 #include "chrome/browser/thumbnails/thumbnailing_context.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
 namespace content {
 class RenderViewHost;
 class RenderWidgetHost;
 }
 
 class ThumbnailTabHelper
     : public content::NotificationObserver,
       public content::WebContentsObserver,
       public content::WebContentsUserData<ThumbnailTabHelper> {
  public:
-  virtual ~ThumbnailTabHelper();
+  ~ThumbnailTabHelper() override;
 
   // Enables or disables the function of taking thumbnails.
   // A disabled ThumbnailTabHelper generates no thumbnails although it still
   // continues to receive the notifications from the web contents.
   void set_enabled(bool enabled) { enabled_ = enabled; }
 
  private:
   explicit ThumbnailTabHelper(content::WebContents* contents);
   friend class content::WebContentsUserData<ThumbnailTabHelper>;
 
   // content::NotificationObserver overrides.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) override;
+  void Observe(int type,
+               const content::NotificationSource& source,
+               const content::NotificationDetails& details) override;
 
   // content::WebContentsObserver overrides.
-  virtual void RenderViewDeleted(
-      content::RenderViewHost* render_view_host) override;
-  virtual void DidStartLoading(
-      content::RenderViewHost* render_view_host) override;
-  virtual void NavigationStopped() override;
+  void RenderViewDeleted(content::RenderViewHost* render_view_host) override;
+  void DidStartLoading(content::RenderViewHost* render_view_host) override;
+  void NavigationStopped() override;
 
   // Update the thumbnail of the given tab contents if necessary.
   void UpdateThumbnailIfNecessary(content::WebContents* web_contents);
 
   // Called when a render view host was created for a WebContents.
   void RenderViewHostCreated(content::RenderViewHost* renderer);
 
   // Indicates that the given widget has changed is visibility.
   void WidgetHidden(content::RenderWidgetHost* widget);
 
   bool enabled_;
 
   content::NotificationRegistrar registrar_;
 
   bool load_interrupted_;
 
   DISALLOW_COPY_AND_ASSIGN(ThumbnailTabHelper);
 };
 
 #endif  // CHROME_BROWSER_THUMBNAILS_THUMBNAIL_TAB_HELPER_H_