Always enable Oilpan for EventSource.

Source/core/page/EventSource.h

Index: Source/core/page/EventSource.h
diff --git a/Source/core/page/EventSource.h b/Source/core/page/EventSource.h
index 5f54f88c1f4770d72ae1d3cfc756c856f4fdc5bf..a9eb0a1f0b44607cb572ee7c20b3aa08279c4d8e 100644
--- a/Source/core/page/EventSource.h
+++ b/Source/core/page/EventSource.h
@@ -50,13 +50,12 @@ class ResourceResponse;
 class TextResourceDecoder;
 class ThreadableLoader;
 
-class EventSource final : public EventTargetWithInlineData, public RefCountedWillBeNoBase<EventSource>, private ThreadableLoaderClient, public ActiveDOMObject {
+class EventSource final : public RefCountedGarbageCollectedEventTargetWithInlineData<EventSource>, private ThreadableLoaderClient, public ActiveDOMObject {
     DEFINE_WRAPPERTYPEINFO();
-    REFCOUNTED_EVENT_TARGET(EventSource);
+    REFCOUNTED_GARBAGE_COLLECTED_EVENT_TARGET(EventSource);
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(EventSource);
-    WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(EventSource);
 public:
-    static PassRefPtrWillBeRawPtr<EventSource> create(ExecutionContext*, const String& url, const EventSourceInit&, ExceptionState&);
+    static EventSource* create(ExecutionContext*, const String& url, const EventSourceInit&, ExceptionState&);
     virtual ~EventSource();
 
     static const unsigned long long defaultReconnectDelay;