Oilpan: Replace most of RefPtrs for Event objects with oilpan's transition types

Source/modules/notifications/Notification.cpp

Index: Source/modules/notifications/Notification.cpp
diff --git a/Source/modules/notifications/Notification.cpp b/Source/modules/notifications/Notification.cpp
index 7c67d3280e06d8efa74573f5f7f58116a07fd396..97091595899eb4c3d79d9865dfd5e9633ae33819 100644
--- a/Source/modules/notifications/Notification.cpp
+++ b/Source/modules/notifications/Notification.cpp
@@ -170,7 +170,7 @@ void Notification::requestPermission(ExecutionContext* context, PassOwnPtr<Notif
     NotificationController::from(toDocument(context)->page())->client()->requestPermission(context, callback);
 }
 
-bool Notification::dispatchEvent(PassRefPtr<Event> event)
+bool Notification::dispatchEvent(PassRefPtrWillBeRawPtr<Event> event)
 {
     ASSERT(m_state != Closed);