Oilpan: Remove ref counting from EventTarget and all uses of Pass/RefPtr<EventTarget>.

Source/core/events/Event.cpp

Index: Source/core/events/Event.cpp
diff --git a/Source/core/events/Event.cpp b/Source/core/events/Event.cpp
index d282d64ca3465af9c3d7af09b6711e0f8043d96d..e0a95408c02806e4cb6b5fb50cf09442f6f68f51 100644
--- a/Source/core/events/Event.cpp
+++ b/Source/core/events/Event.cpp
@@ -186,7 +186,7 @@ bool Event::isBeforeUnloadEvent() const
     return false;
 }
 
-void Event::setTarget(PassRefPtr<EventTarget> target)
+void Event::setTarget(PassRefPtrWillBeRawPtr<EventTarget> target)
 {
     if (m_target == target)
         return;