Use "unsigned" rather than "unsigned long" for C++ code interacting with WebIDL's "unsigned long".

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 116 matching lines @@
     void overrideMimeType(const AtomicString& override, ExceptionState&);
     String getAllResponseHeaders() const;
     const AtomicString& getResponseHeader(const AtomicString&) const;
     ScriptString responseText(ExceptionState&);
     ScriptString responseJSONSource();
     Document* responseXML(ExceptionState&);
     Blob* responseBlob();
     DOMArrayBuffer* responseArrayBuffer();
     Stream* responseLegacyStream();
     ReadableStream* responseStream();
-    unsigned long timeout() const { return m_timeoutMilliseconds; }
-    void setTimeout(unsigned long timeout, ExceptionState&);
+    unsigned timeout() const { return m_timeoutMilliseconds; }
+    void setTimeout(unsigned timeout, ExceptionState&);
     ResponseTypeCode responseTypeCode() const { return m_responseTypeCode; }
     String responseType();
     void setResponseType(const String&, ExceptionState&);
     String responseURL();
 
     // For Inspector.
     void sendForInspectorXHRReplay(PassRefPtr<FormData>, ExceptionState&);
 
     XMLHttpRequestUpload* upload();
 
@@ skipping 155 matching lines @@
     bool m_uploadComplete;
     bool m_sameOriginRequest;
     // True iff the ongoing resource loading is using the downloadToFile
     // option.
     bool m_downloadingToFile;
 };
 
 } // namespace blink
 
 #endif // XMLHttpRequest_h