Prevent ThreadableLoaderClient methods from being called after failure notification

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 97 matching lines @@
     template<> struct CrossThreadCopierBase<false, false, false, ThreadableLoaderOptions> {
         typedef CrossThreadThreadableLoaderOptionsData Type;
         static Type copy(const ThreadableLoaderOptions& options)
         {
             return CrossThreadThreadableLoaderOptionsData(options);
         }
     };
 
     // Useful for doing loader operations from any thread (not threadsafe,
     // just able to run on threads other than the main thread).
+    //
+    // Arguments common to both loadResourceSynchronously() and create():
+    //
+    // - 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.
     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&);
+        // The following ThreadableLoaderClient methods may destroy the
+        // ThreadableLoader instance in them.
+        // - didFinishLoading()
+        // - didFail()
+        // - didFailAccessControlCheck()
+        // - didFailRedirectCheck()
         static PassRefPtr<ThreadableLoader> create(ExecutionContext&, ThreadableLoaderClient*, const ResourceRequest&, const ThreadableLoaderOptions&, const ResourceLoaderOptions&);
 
         // 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