Improve fidelity of XHR progress events.

Source/core/xml/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 166 matching lines @@
     // Clears variables used only while the resource is being loaded.
     void clearVariablesForLoading();
     // Returns false iff reentry happened and a new load is started.
     bool internalAbort(DropProtection = DropProtectionSync);
     // Clears variables holding response header and body data.
     void clearResponse();
     void clearRequest();
 
     void createRequest(ExceptionState&);
 
-    // Dispatches an event of the specified type to m_upload and
-    // m_progressEventThrottle.
-    void dispatchEventAndLoadEnd(const AtomicString&);
+    // Dispatches an event of the specified type to m_progressEventThrottle.
+    void dispatchEventAndLoadEnd(const AtomicString&, long long, long long);
 
-    void dispatchThrottledProgressEvent();
+    // Dispatches a response progress event to m_progressEventThrottle.
+    void dispatchThrottledProgressEvent(const AtomicString&, long long, long long);
+
+    // Dispatches a response progress event using values sampled from
+    // m_receivedLength and m_response.
+    void dispatchThrottledProgressEventSnapshot(const AtomicString&);
 
     // Does clean up common for all kind of didFail() call.
     void handleDidFailGeneric();
     // Handles didFail() call not caused by cancellation or timeout.
     void handleNetworkError();
     // Handles didFail() call triggered by m_loader->cancel().
     void handleDidCancel();
     // Handles didFail() call for timeout.
     void handleDidTimeout();
 
-    void handleRequestError(ExceptionCode, const AtomicString&);
+    void handleRequestError(ExceptionCode, const AtomicString&, long long, long long);
 
     OwnPtr<XMLHttpRequestUpload> m_upload;
 
     KURL m_url;
     String m_method;
     HTTPHeaderMap m_requestHeaders;
     RefPtr<FormData> m_requestEntityBody;
     String m_mimeTypeOverride;
     bool m_async;
     bool m_includeCredentials;
@@ skipping 39 matching lines @@
 
     // An enum corresponding to the allowed string values for the responseType attribute.
     ResponseTypeCode m_responseTypeCode;
     AsyncMethodRunner<XMLHttpRequest> m_dropProtectionRunner;
     RefPtr<SecurityOrigin> m_securityOrigin;
 };
 
 } // namespace WebCore
 
 #endif // XMLHttpRequest_h