Add gapless playback support for AAC playback.

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 549 matching lines @@
       if (!audio_) {
         DVLOG(1) << "Failed to create an audio stream.";
         return false;
       }
 
       if (!frame_processor_->AddTrack(FrameProcessorBase::kAudioTrackId,
                                       audio_)) {
         DVLOG(1) << "Failed to add audio track to frame processor.";
         return false;
       }
+    } else {
+      frame_processor_->clear_audio_preroll_buffer();
     }
 
     success &= audio_->UpdateAudioConfig(audio_config, log_cb_);
   }
 
   if (video_config.IsValidConfig()) {
     if (!video_) {
       video_ = create_demuxer_stream_cb_.Run(DemuxerStream::VIDEO);
 
       if (!video_) {
@@ skipping 1155 matching lines @@
 }
 
 void ChunkDemuxer::ShutdownAllStreams() {
   for (SourceStateMap::iterator itr = source_state_map_.begin();
        itr != source_state_map_.end(); ++itr) {
     itr->second->Shutdown();
   }
 }
 
 }  // namespace media