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

Source/core/xmlhttprequest/XMLHttpRequest.h

Index: Source/core/xmlhttprequest/XMLHttpRequest.h
diff --git a/Source/core/xmlhttprequest/XMLHttpRequest.h b/Source/core/xmlhttprequest/XMLHttpRequest.h
index d7151be5273c7067de03b8420e1cf2a38248c3bb..2c1f14f5e6b9a160c163048ccec703b1f6fe3b31 100644
--- a/Source/core/xmlhttprequest/XMLHttpRequest.h
+++ b/Source/core/xmlhttprequest/XMLHttpRequest.h
@@ -134,8 +134,8 @@ public:
     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&);