[Fetch, Loader] Expect on-heap objects will never get destroyed with a reference

third_party/WebKit/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 113 matching lines @@
 //   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 GarbageCollectedFinalized<ThreadableLoader> {
   WTF_MAKE_NONCOPYABLE(ThreadableLoader);
 
  public:
-  // ThreadableLoaderClient methods may not destroy the ThreadableLoader
-  // instance in them.
   static void loadResourceSynchronously(ExecutionContext&,
                                         const ResourceRequest&,
                                         ThreadableLoaderClient&,
                                         const ThreadableLoaderOptions&,
                                         const ResourceLoaderOptions&);
 
   // This method never returns nullptr.
   //
   // This method must always be followed by start() call.
   // ThreadableLoaderClient methods are never called before start() call.
@@ skipping 15 matching lines @@
   // A user must guarantee that the loading completes before the attached
   // client gets invalid. Also, a user must guarantee that the loading
   // completes before the ThreadableLoader is destructed.
   //
   // When ThreadableLoader::cancel() is called,
   // ThreadableLoaderClient::didFail() is called with a ResourceError
   // with isCancellation() returning true, if any of didFinishLoading()
   // or didFail.*() methods have not been called yet. (didFail() may be
   // called with a ResourceError with isCancellation() returning true
   // also for cancellation happened inside the loader.)
-  //
-  // ThreadableLoaderClient methods:

[hiroshige, 2016/10/21 05:45:14]

Isn't the part of "ThreadableLoaderClient methods may call cancel()" still
valid?

[yhirano, 2016/10/26 11:09:34]

You're right, thanks.

-  // - may call cancel()
-  // - can destroy the ThreadableLoader instance in them (by clearing
-  //   std::unique_ptr<ThreadableLoader>).
   static ThreadableLoader* create(ExecutionContext&,
                                   ThreadableLoaderClient*,
                                   const ThreadableLoaderOptions&,
                                   const ResourceLoaderOptions&);
 
   // The methods on the ThreadableLoaderClient passed on create() call
   // 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
@@ skipping 10 matching lines @@
 
   DEFINE_INLINE_VIRTUAL_TRACE() {}
 
  protected:
   ThreadableLoader() {}
 };
 
 }  // namespace blink
 
 #endif  // ThreadableLoader_h