Enable Oilpan for core/clipboard/

Source/core/events/MouseEvent.h

Index: Source/core/events/MouseEvent.h
diff --git a/Source/core/events/MouseEvent.h b/Source/core/events/MouseEvent.h
index 57237840f5855253fa33f2cc4f1fad78dfff3e98..3416c30b5e1c9153015e3374f72711e9c0391b12 100644
--- a/Source/core/events/MouseEvent.h
+++ b/Source/core/events/MouseEvent.h
@@ -47,7 +47,7 @@ public:
         int detail, int screenX, int screenY, int windowX, int windowY,
         int movementX, int movementY,
         bool ctrlKey, bool altKey, bool shiftKey, bool metaKey, unsigned short button, unsigned short buttons,
-        PassRefPtrWillBeRawPtr<EventTarget> relatedTarget, PassRefPtrWillBeRawPtr<DataTransfer>,
+        PassRefPtrWillBeRawPtr<EventTarget> relatedTarget, DataTransfer*,
         bool isSimulated = false, PlatformMouseEvent::SyntheticEventType = PlatformMouseEvent::RealOrIndistinguishable,
         double uiCreateTime = 0);
 
@@ -92,7 +92,7 @@ protected:
         int detail, int screenX, int screenY, int windowX, int windowY,
         int movementX, int movementY,
         bool ctrlKey, bool altKey, bool shiftKey, bool metaKey, unsigned short button, unsigned short buttons,
-        PassRefPtrWillBeRawPtr<EventTarget> relatedTarget, PassRefPtrWillBeRawPtr<DataTransfer>,
+        PassRefPtrWillBeRawPtr<EventTarget> relatedTarget, DataTransfer*,
         bool isSimulated, PlatformMouseEvent::SyntheticEventType, double uiCreateTime = 0);
 
     MouseEvent(const AtomicString& type, const MouseEventInit&);
@@ -104,7 +104,7 @@ private:
     unsigned short m_buttons;
     bool m_buttonDown;
     RefPtrWillBeMember<EventTarget> m_relatedTarget;
-    RefPtrWillBeMember<DataTransfer> m_dataTransfer;
+    PersistentWillBeMember<DataTransfer> m_dataTransfer;
     PlatformMouseEvent::SyntheticEventType m_syntheticEventType;
 };