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

Source/core/dom/Document.h

Index: Source/core/dom/Document.h
diff --git a/Source/core/dom/Document.h b/Source/core/dom/Document.h
index 1dc5c9aca881f3d767218ca69578d47d32fc6570..f26313d5b72c24941ca9836e55aea6283b557ee2 100644
--- a/Source/core/dom/Document.h
+++ b/Source/core/dom/Document.h
@@ -95,6 +95,7 @@ class DocumentType;
 class Element;
 class ElementDataCache;
 class Event;
+class EventFactoryBase;
 class EventListener;
 class ExceptionState;
 class FastTextAutosizer;
@@ -693,6 +694,7 @@ public:
     void setWindowAttributeEventListener(const AtomicString& eventType, PassRefPtr<EventListener>);
     EventListener* getWindowAttributeEventListener(const AtomicString& eventType);
 
+    static void registerEventFactory(EventFactoryBase*);
     static PassRefPtrWillBeRawPtr<Event> createEvent(const String& eventType, ExceptionState&);
 
     // keep track of what types of event listeners are registered, so we don't
@@ -1181,6 +1183,9 @@ private:
 
     bool haveStylesheetsLoaded() const;
 
+    typedef HashSet<EventFactoryBase*> EventFactorySet;
+    static EventFactorySet& eventFactories();
+
     DocumentLifecycle m_lifecycle;
 
     bool m_hasNodesWithPlaceholderStyle;