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

Source/core/events/EventFactory.h

Index: Source/core/events/EventFactory.h
diff --git a/Source/core/events/EventFactory.h b/Source/core/events/EventFactory.h
index fae23e9e1a7f895e5ffb2d7a2f3349f56efb3b64..78f7be1869a60a7998f61bf87d599d185b67f46d 100644
--- a/Source/core/events/EventFactory.h
+++ b/Source/core/events/EventFactory.h
@@ -34,9 +34,14 @@ 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;
 };
 
 }