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

Source/core/loader/ThreadableLoader.h

 /*
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 106 matching lines @@
     // just able to run on threads other than the main thread).
     class CORE_EXPORT ThreadableLoader : public RefCounted<ThreadableLoader> {
         WTF_MAKE_NONCOPYABLE(ThreadableLoader);
     public:
         // ThreadableLoaderOptions argument configures this ThreadableLoader's
         // behavior.
         //
         // ResourceLoaderOptions argument will be passed to the FetchRequest
         // that this ThreadableLoader creates. It can be altered e.g. when
         // redirect happens.
+
         static void loadResourceSynchronously(ExecutionContext&, const ResourceRequest&, ThreadableLoaderClient&, const ThreadableLoaderOptions&, const ResourceLoaderOptions&);
-        static PassRefPtr<ThreadableLoader> create(ExecutionContext&, ThreadableLoaderClient*, const ResourceRequest&, const ThreadableLoaderOptions&, const ResourceLoaderOptions&);
+        // create() must always followed by start() call.

[hiroshige, 2015/08/10 15:00:05]

Please mention that create() never returns null.

[tyoshino (SeeGerritForStatus), 2016/01/29 12:36:52]

Done.

[tyoshino (SeeGerritForStatus), 2016/01/29 12:37:56]

This reply had to be published before.

+        // |ThreadableLoaderClient| methods are never called before start() call.
+        static PassRefPtr<ThreadableLoader> create(ExecutionContext&, ThreadableLoaderClient*, const ThreadableLoaderOptions&, const ResourceLoaderOptions&);
+
+        // The methods on the |ThreadableLoaderClient| may be called
+        // synchronous to start() call.
+        virtual void start(const ResourceRequest&) = 0;
 
         // A ThreadableLoader may have a timeout specified. It is possible, in some cases, for
         // the timeout to be overridden after the request is sent (for example, XMLHttpRequests
         // may override their timeout setting after sending).
         //
         // Set a new timeout relative to the time the request started, in milliseconds.
         virtual void overrideTimeout(unsigned long timeoutMilliseconds) = 0;
 
         virtual void cancel() = 0;
 
         virtual ~ThreadableLoader() { }
 
     protected:
         ThreadableLoader() { }
     };
 
 } // namespace blink
 
 #endif // ThreadableLoader_h