Oilpan: Move the EventListener hierarchy to Oilpan's heap

Source/modules/encryptedmedia/HTMLMediaElementEncryptedMedia.h

Index: Source/modules/encryptedmedia/HTMLMediaElementEncryptedMedia.h
diff --git a/Source/modules/encryptedmedia/HTMLMediaElementEncryptedMedia.h b/Source/modules/encryptedmedia/HTMLMediaElementEncryptedMedia.h
index 9e210715821304b016f87b64ed79cabce0ef7bec..a990cae294456a827078ce6502047de56d24338f 100644
--- a/Source/modules/encryptedmedia/HTMLMediaElementEncryptedMedia.h
+++ b/Source/modules/encryptedmedia/HTMLMediaElementEncryptedMedia.h
@@ -65,7 +65,7 @@ private:
     void cancelKeyRequest(WebMediaPlayer*, const String& keySystem, const String& sessionId, ExceptionState&);
 
     // EventTarget
-    bool setAttributeEventListener(const AtomicString& eventType, PassRefPtr<EventListener>);
+    bool setAttributeEventListener(const AtomicString& eventType, PassRefPtrWillBeRawPtr<EventListener>);
     EventListener* getAttributeEventListener(const AtomicString& eventType);
 
     // Currently we have both EME v0.1b and EME WD implemented in media element.