Use method registration approach for creating events on core and modules.

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 16 matching lines @@
 #define EventFactory_h
 
 #include "platform/heap/Handle.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/text/AtomicString.h"
 
 namespace WebCore {
 
 class Event;
 
-class EventFactory {
+class EventFactoryBase {
 public:
-    static PassRefPtrWillBeRawPtr<Event> create(const String& eventType);
+    virtual PassRefPtrWillBeRawPtr<Event> create(const String& eventType) = 0;
+};
+
+class EventFactory : public EventFactoryBase {
+public:
+    virtual PassRefPtrWillBeRawPtr<Event> create(const String& eventType) OVERRIDE;
 };
 
 }
 
 #endif