Pipeline: Use WeakPtr for DemuxerHost Calls and Tasks.

media/base/pipeline.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_PIPELINE_H_
 #define MEDIA_BASE_PIPELINE_H_
 
 #include <string>
 
 #include "base/gtest_prod_util.h"
@@ skipping 412 matching lines @@
 
   scoped_ptr<SerialRunner> pending_callbacks_;
 
   bool underflow_disabled_for_testing_;
 
   base::ThreadChecker thread_checker_;
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<Pipeline> weak_factory_;
 
+  // Demuxer calls can be made on the render main thread, where we cannot call
+  // weak_factory_.GetWeakPtr() to get weak pointers. Instead, use a permanent

[scherkus (not reviewing), 2014/08/05 18:11:30]

you sure about this?

I'm fairly certain GetWeakPtr() is OK to call on different threads, it's that
you cannot inspect/dereference the pointer on a different thread 

[xhwang, 2014/08/05 20:44:46]

Cool, I didn't know that. Double checked weak_ptr.h and you are right. This
actually makes the CL much simpler.

+  // weak pointer which will be initialized during the Demuxer initialization.
+  base::WeakPtr<Pipeline> weak_this_for_demuxer_;
+
   DISALLOW_COPY_AND_ASSIGN(Pipeline);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_PIPELINE_H_