Oilpan: make XHR progress event throttling finalization safe.

Source/core/xmlhttprequest/XMLHttpRequest.h

 /*
  *  Copyright (C) 2003, 2006, 2008 Apple Inc. All rights reserved.
  *  Copyright (C) 2005, 2006 Alexey Proskuryakov <ap@nypop.com>
  *  Copyright (C) 2011 Google Inc. All rights reserved.
  *  Copyright (C) 2012 Intel Corporation
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
  *  License as published by the Free Software Foundation; either
  *  version 2 of the License, or (at your option) any later version.
@@ skipping 236 matching lines @@
     void handleNetworkError();
     // Handles didFail() call for cancellations. For example, the
     // ResourceLoader handling the load notifies m_loader of an error
     // cancellation when the frame containing the XHR navigates away.
     void handleDidCancel();
     // Handles didFail() call for timeout.
     void handleDidTimeout();
 
     void handleRequestError(ExceptionCode, const AtomicString&, long long, long long);
 
+    XMLHttpRequestProgressEventThrottle& progressEventThrottle();
+
     OwnPtrWillBeMember<XMLHttpRequestUpload> m_upload;
 
     KURL m_url;
     AtomicString m_method;
     HTTPHeaderMap m_requestHeaders;
     // Not converted to ASCII lowercase. Must be lowered later or compared
     // using case insensitive comparison functions if needed.
     AtomicString m_mimeTypeOverride;
     unsigned long m_timeoutMilliseconds;
     PersistentWillBeMember<Blob> m_responseBlob;
@@ skipping 19 matching lines @@
     RefPtr<DOMArrayBuffer> m_responseArrayBuffer;
 
     // Used for onprogress tracking
     long long m_receivedLength;
 
     // An exception to throw in synchronous mode. It's set when failure
     // notification is received from m_loader and thrown at the end of send() if
     // any.
     ExceptionCode m_exceptionCode;
 
-    XMLHttpRequestProgressEventThrottle m_progressEventThrottle;
+    OwnPtrWillBeMember<XMLHttpRequestProgressEventThrottle> m_progressEventThrottle;
 
     // An enum corresponding to the allowed string values for the responseType attribute.
     ResponseTypeCode m_responseTypeCode;
     RefPtr<SecurityOrigin> m_securityOrigin;
 
     // This blob loader will be used if |m_downloadingToFile| is true and
     // |m_responseTypeCode| is NOT ResponseTypeBlob.
     PersistentWillBeMember<BlobLoader> m_blobLoader;
 
     // Positive if we are dispatching events.
@@ skipping 12 matching lines @@
     bool m_sameOriginRequest;
     // True iff the ongoing resource loading is using the downloadToFile
     // option.
     bool m_downloadingToFile;
     bool m_responseTextOverflow;
 };
 
 } // namespace blink
 
 #endif // XMLHttpRequest_h