Add <menuitem>, new HTMLMenuElement IDL attributes.

Source/core/events/RelatedEvent.h

Index: Source/core/events/RelatedEvent.h
diff --git a/Source/core/events/RelatedEvent.h b/Source/core/events/RelatedEvent.h
index 82c3a6fe4726d7c3fb8c7f5d46e24aa5fd827fb5..e1ec1ae467b38fbe5370dc55ddc82ba5230eeafe 100644
--- a/Source/core/events/RelatedEvent.h
+++ b/Source/core/events/RelatedEvent.h
@@ -23,8 +23,6 @@ public:
     virtual ~RelatedEvent();
 
     EventTarget* relatedTarget() const { return m_relatedTarget.get(); }
-    void setRelatedTarget(EventTarget* relatedTarget) { m_relatedTarget = relatedTarget; }
-
 
     virtual const AtomicString& interfaceName() const OVERRIDE { return EventNames::RelatedEvent; }
     virtual bool isRelatedEvent() const OVERRIDE { return true; }