Avoid double task trampoline for Pipeline state transitions.

media/filters/chunk_demuxer.cc

 // 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.
 
 #include "media/filters/chunk_demuxer.h"
 
 #include <algorithm>
 #include <limits>
 #include <list>
 
@@ skipping 1114 matching lines @@
 }
 
 void ChunkDemuxer::Initialize(
     DemuxerHost* host,
     const PipelineStatusCB& cb,
     bool enable_text_tracks) {
   DVLOG(1) << "Init()";
 
   base::AutoLock auto_lock(lock_);
 
+  // The |init_cb_| must only be run after this method returns, so always post.
   init_cb_ = BindToCurrentLoop(cb);
   if (state_ == SHUTDOWN) {
     base::ResetAndReturn(&init_cb_).Run(DEMUXER_ERROR_COULD_NOT_OPEN);
     return;
   }
   DCHECK_EQ(state_, WAITING_FOR_INIT);
   host_ = host;
   enable_text_ = enable_text_tracks;
 
   ChangeState_Locked(INITIALIZING);
@@ skipping 707 matching lines @@
 }
 
 void ChunkDemuxer::ShutdownAllStreams() {
   for (SourceStateMap::iterator itr = source_state_map_.begin();
        itr != source_state_map_.end(); ++itr) {
     itr->second->Shutdown();
   }
 }
 
 }  // namespace media