Oilpan: Prepare to move EventDispatchMediator to Oilpan heap.

Source/core/events/MouseEvent.cpp

Index: Source/core/events/MouseEvent.cpp
diff --git a/Source/core/events/MouseEvent.cpp b/Source/core/events/MouseEvent.cpp
index 4c966f1b7264496e1ab8d19865256d55b8c12a38..47977893d00f9a566df0487f2c2a2a7ef746a13f 100644
--- a/Source/core/events/MouseEvent.cpp
+++ b/Source/core/events/MouseEvent.cpp
@@ -231,9 +231,9 @@ void SimulatedMouseEvent::trace(Visitor* visitor)
     MouseEvent::trace(visitor);
 }
 
-PassRefPtr<MouseEventDispatchMediator> MouseEventDispatchMediator::create(PassRefPtrWillBeRawPtr<MouseEvent> mouseEvent, MouseEventType mouseEventType)
+PassRefPtrWillBeRawPtr<MouseEventDispatchMediator> MouseEventDispatchMediator::create(PassRefPtrWillBeRawPtr<MouseEvent> mouseEvent, MouseEventType mouseEventType)
 {
-    return adoptRef(new MouseEventDispatchMediator(mouseEvent, mouseEventType));
+    return adoptRefWillBeNoop(new MouseEventDispatchMediator(mouseEvent, mouseEventType));
 }
 
 MouseEventDispatchMediator::MouseEventDispatchMediator(PassRefPtrWillBeRawPtr<MouseEvent> mouseEvent, MouseEventType mouseEventType)