Correct data size argument type in resource loading path to unsigned

Source/core/workers/WorkerScriptLoader.cpp

 /*
  * Copyright (C) 2009 Apple Inc. All Rights Reserved.
  * Copyright (C) 2009, 2011 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 104 matching lines @@
     if (response.httpStatusCode() / 100 != 2 && response.httpStatusCode()) {
         m_failed = true;
         return;
     }
     m_responseURL = response.url();
     m_responseEncoding = response.textEncodingName();
     if (m_client)
         m_client->didReceiveResponse(identifier, response);
 }
 
-void WorkerScriptLoader::didReceiveData(const char* data, int len)
+void WorkerScriptLoader::didReceiveData(const char* data, unsigned len)
 {
     if (m_failed)
         return;
 
     if (!m_decoder) {
         if (!m_responseEncoding.isEmpty())
             m_decoder = TextResourceDecoder::create("text/javascript", m_responseEncoding);
         else
             m_decoder = TextResourceDecoder::create("text/javascript", "UTF-8");
     }
 
     if (!len)
         return;
 
-    if (len == -1)
-        len = strlen(data);
-
     m_script.append(m_decoder->decode(data, len));
 }
 
 void WorkerScriptLoader::didFinishLoading(unsigned long identifier, double)
 {
     if (m_failed) {
         notifyError();
         return;
     }
 
@@ skipping 34 matching lines @@
 void WorkerScriptLoader::notifyFinished()
 {
     if (!m_client || m_finishing)
         return;
 
     m_finishing = true;
     m_client->notifyFinished();
 }
 
 } // namespace blink