Fix virtual/override/final usage in Source/web/.

Source/web/NotificationPermissionClientImpl.cpp

Index: Source/web/NotificationPermissionClientImpl.cpp
diff --git a/Source/web/NotificationPermissionClientImpl.cpp b/Source/web/NotificationPermissionClientImpl.cpp
index d012ee83b60000fb911f418914eedaaad21a29b5..6430996d46d5a7c10bc2df7a39d7ccf2044c59cc 100644
--- a/Source/web/NotificationPermissionClientImpl.cpp
+++ b/Source/web/NotificationPermissionClientImpl.cpp
@@ -23,9 +23,9 @@ public:
     {
     }
 
-    virtual ~WebNotificationPermissionCallbackImpl() { }
+    ~WebNotificationPermissionCallbackImpl() override { }
 
-    virtual void permissionRequestComplete(WebNotificationPermission permission) override
+    void permissionRequestComplete(WebNotificationPermission permission) override
     {
         if (m_callback)
             m_callback->handleEvent(Notification::permissionString(permission));