Oilpan: Prepare to move EventDispatchMediator to Oilpan heap.

Source/core/dom/Node.cpp

Index: Source/core/dom/Node.cpp
diff --git a/Source/core/dom/Node.cpp b/Source/core/dom/Node.cpp
index 5e8678b6ec3d5cfc7f7bd52e53439f1e99f7ae70..7e594e2c22d24f0e659d55838f6f144e6be7f0d0 100644
--- a/Source/core/dom/Node.cpp
+++ b/Source/core/dom/Node.cpp
@@ -2203,7 +2203,7 @@ void Node::dispatchScopedEvent(PassRefPtrWillBeRawPtr<Event> event)
     dispatchScopedEventDispatchMediator(EventDispatchMediator::create(event));
 }
 
-void Node::dispatchScopedEventDispatchMediator(PassRefPtr<EventDispatchMediator> eventDispatchMediator)
+void Node::dispatchScopedEventDispatchMediator(PassRefPtrWillBeRawPtr<EventDispatchMediator> eventDispatchMediator)
 {
     EventDispatcher::dispatchScopedEvent(this, eventDispatchMediator);
 }