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

chrome/browser/notifications/extension_welcome_notification.h

Index: chrome/browser/notifications/extension_welcome_notification.h
diff --git a/chrome/browser/notifications/extension_welcome_notification.h b/chrome/browser/notifications/extension_welcome_notification.h
index fd26c078487c287f0992246bbf826feb0cd4b7fa..8a46fb9fafa5425e31d65b717a0104e548667450 100644
--- a/chrome/browser/notifications/extension_welcome_notification.h
+++ b/chrome/browser/notifications/extension_welcome_notification.h
@@ -64,7 +64,7 @@ class ExtensionWelcomeNotification : public KeyedService,
   // The extension Id associated with the Google Now extension.
   static const char kChromeNowExtensionID[];
 
-  virtual ~ExtensionWelcomeNotification();
+  ~ExtensionWelcomeNotification() override;
 
   // To workaround the lack of delegating constructors prior to C++11, we use
   // static Create methods.
@@ -76,7 +76,7 @@ class ExtensionWelcomeNotification : public KeyedService,
                                               Delegate* const delegate);
 
   // PrefServiceSyncableObserver
-  virtual void OnIsSyncingChanged() override;
+  void OnIsSyncingChanged() override;
 
   // Adds in the welcome notification if required for components built
   // into Chrome that show notifications like Chrome Now.