Oilpan: Remove guardRef and guardDeref from TreeScope.

Source/core/html/imports/HTMLImportChild.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 16 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef HTMLImportChild_h
 #define HTMLImportChild_h
 
 #include "core/fetch/RawResource.h"
 #include "core/fetch/ResourceOwner.h"
 #include "core/html/imports/HTMLImport.h"
+#include "heap/Handle.h"
 #include "platform/weborigin/KURL.h"
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class CustomElementMicrotaskImportStep;
 class HTMLImportLoader;
 class HTMLImportChildClient;
 class HTMLLinkElement;
 
@@ skipping 44 matching lines @@
     // HTMLImportChild owns the resource so that the contents of prefetched Resource doesn't go away.
     virtual void responseReceived(Resource*, const ResourceResponse&) OVERRIDE { }
     virtual void dataReceived(Resource*, const char*, int) OVERRIDE { }
     virtual void notifyFinished(Resource*) OVERRIDE { }
 
     void didFinish();
     void createLoader();
     void shareLoader(HTMLImportChild*);
     void ensureLoader();
 
+#if ENABLE(OILPAN)
+    Persistent<Document> m_master;
+#else
     Document& m_master;
+#endif
     KURL m_url;
     CustomElementMicrotaskImportStep* m_customElementMicrotaskStep;
     HTMLImportLoader* m_loader;
     HTMLImportChildClient* m_client;
 };
 
 inline HTMLImportChild* toHTMLImportChild(HTMLImport* import)
 {
     ASSERT(!import || import->isChild());
     return static_cast<HTMLImportChild*>(import);
 }
 
 } // namespace WebCore
 
 #endif // HTMLImportChild_h