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

chrome/browser/ui/webui/help/help_handler.h

Index: chrome/browser/ui/webui/help/help_handler.h
diff --git a/chrome/browser/ui/webui/help/help_handler.h b/chrome/browser/ui/webui/help/help_handler.h
index 9454e1b6aea430c11a1bd21e1ce433c748a041e2..18646049c7dd80acc59bca3b22c936c5f718e532 100644
--- a/chrome/browser/ui/webui/help/help_handler.h
+++ b/chrome/browser/ui/webui/help/help_handler.h
@@ -30,17 +30,18 @@ class HelpHandler : public content::WebUIMessageHandler,
                     public content::NotificationObserver {
  public:
   HelpHandler();
-  virtual ~HelpHandler();
+  ~HelpHandler() override;
 
   // WebUIMessageHandler implementation.
-  virtual void RegisterMessages() override;
+  void RegisterMessages() override;
 
   // Adds string values for the UI to |localized_strings|.
   static void GetLocalizedValues(base::DictionaryValue* localized_strings);
 
   // NotificationObserver implementation.
-  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;
 
   // Returns the browser version as a string.
   static base::string16 BuildBrowserVersionString();