Oilpan: use transition types for remaining RefPtr<Document>s in dom/.

Source/core/timing/PerformanceResourceTiming.h

Index: Source/core/timing/PerformanceResourceTiming.h
diff --git a/Source/core/timing/PerformanceResourceTiming.h b/Source/core/timing/PerformanceResourceTiming.h
index 3fbe6be1323addf42031c0b2072132564c29f44d..a8032bd869579c5ef9ef2f66783161e877262728 100644
--- a/Source/core/timing/PerformanceResourceTiming.h
+++ b/Source/core/timing/PerformanceResourceTiming.h
@@ -74,10 +74,7 @@ public:
 
     virtual bool isResource() OVERRIDE { return true; }
 
-    virtual void trace(Visitor* visitor)
-    {
-        PerformanceEntry::trace(visitor);
-    }
+    virtual void trace(Visitor*) OVERRIDE;
 
 private:
     PerformanceResourceTiming(const ResourceTimingInfo&, Document* requestingDocument, double startTime, double lastRedirectEndTime, bool m_allowTimingDetails, bool m_allowRedirectDetails);
@@ -90,7 +87,7 @@ private:
     bool m_didReuseConnection;
     bool m_allowTimingDetails;
     bool m_allowRedirectDetails;
-    RefPtr<Document> m_requestingDocument;
+    RefPtrWillBeMember<Document> m_requestingDocument;
 };
 
 }