Fix virtual/override/final usage in the rest of Source/core/.

Source/core/events/EventFactory.h

 /*
  * Copyright (C) 2011 Google, Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 32 matching lines @@
     EventFactoryBase() { }
 };
 
 class EventFactory final : public EventFactoryBase {
 public:
     static PassOwnPtr<EventFactory> create()
     {
         return adoptPtr(new EventFactory());
     }
 
-    virtual PassRefPtrWillBeRawPtr<Event> create(const String& eventType) override;
+    PassRefPtrWillBeRawPtr<Event> create(const String& eventType) override;
 };
 
 }
 
 #endif