Split the constructor of ThreadableLoader into two methods (ctor and start())

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 83 matching lines @@
     if (!request)
         return;
 
     ThreadableLoaderOptions options;
     options.crossOriginRequestPolicy = crossOriginRequestPolicy;
 
     ResourceLoaderOptions resourceLoaderOptions;
     resourceLoaderOptions.allowCredentials = AllowStoredCredentials;
 
     m_needToCancel = true;
-    m_threadableLoader = ThreadableLoader::create(executionContext, this, *request, options, resourceLoaderOptions);
+    m_threadableLoader = ThreadableLoader::create(executionContext, this, options, resourceLoaderOptions);
+    m_threadableLoader->start(*request);
     if (m_failed)
         notifyFinished();
     // Do nothing here since notifyFinished() could delete |this|.
 }
 
 const KURL& WorkerScriptLoader::responseURL() const
 {
     ASSERT(!failed());
     return m_responseURL;
 }
@@ skipping 110 matching lines @@
     // document (which is implemented in WorkerMessagingProxy, and
     // m_contentSecurityPolicy should be left as nullptr to inherit the policy).
     if (!response.url().protocolIs("blob") && !response.url().protocolIs("file") && !response.url().protocolIs("filesystem")) {
         m_contentSecurityPolicy = ContentSecurityPolicy::create();
         m_contentSecurityPolicy->setOverrideURLForSelf(response.url());
         m_contentSecurityPolicy->didReceiveHeaders(ContentSecurityPolicyResponseHeaders(response));
     }
 }
 
 } // namespace blink