Introduce DECLARE_FORWARDING_ATTRIBUTE_EVENT_LISTENER() macro

Source/core/dom/EventTarget.h

Index: Source/core/dom/EventTarget.h
diff --git a/Source/core/dom/EventTarget.h b/Source/core/dom/EventTarget.h
index 2d8a0a90c174a4c65e60e8c704a4182c479d33bf..db533917b47fd9fecb02934367360ca8c5220bd2 100644
--- a/Source/core/dom/EventTarget.h
+++ b/Source/core/dom/EventTarget.h
@@ -165,9 +165,13 @@ namespace WebCore {
         EventListener* on##attribute(DOMWrapperWorld* isolatedWorld) { return getAttributeEventListener(eventNames().eventName##Event, isolatedWorld); } \
         void setOn##attribute(PassRefPtr<EventListener> listener, DOMWrapperWorld* isolatedWorld) { setAttributeEventListener(eventNames().eventName##Event, listener, isolatedWorld); } \
 
-    #define DEFINE_FORWARDING_ATTRIBUTE_EVENT_LISTENER(recipient, attribute) \
-        EventListener* on##attribute(DOMWrapperWorld* isolatedWorld) { return recipient ? recipient->getAttributeEventListener(eventNames().attribute##Event, isolatedWorld) : 0; } \
-        void setOn##attribute(PassRefPtr<EventListener> listener, DOMWrapperWorld* isolatedWorld) { if (recipient) recipient->setAttributeEventListener(eventNames().attribute##Event, listener, isolatedWorld); } \
+    #define DECLARE_FORWARDING_ATTRIBUTE_EVENT_LISTENER(recipient, attribute) \
+        EventListener* on##attribute(DOMWrapperWorld* isolatedWorld); \
+        void setOn##attribute(PassRefPtr<EventListener> listener, DOMWrapperWorld* isolatedWorld);
+
+    #define DEFINE_FORWARDING_ATTRIBUTE_EVENT_LISTENER(type, recipient, attribute) \
+        EventListener* type::on##attribute(DOMWrapperWorld* isolatedWorld) { return recipient ? recipient->getAttributeEventListener(eventNames().attribute##Event, isolatedWorld) : 0; } \
+        void type::setOn##attribute(PassRefPtr<EventListener> listener, DOMWrapperWorld* isolatedWorld) { if (recipient) recipient->setAttributeEventListener(eventNames().attribute##Event, listener, isolatedWorld); }
 
     inline bool EventTarget::isFiringEventListeners()
     {