Fix ChunkDemuxer seek deadlock

media/filters/ffmpeg_audio_decoder.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/ffmpeg_audio_decoder.h"
 
 #include "base/bind.h"
 #include "media/base/audio_decoder_config.h"
 #include "media/base/data_buffer.h"
 #include "media/base/demuxer.h"
@@ skipping 151 matching lines @@
   CHECK(read_cb_.is_null()) << "Overlapping decodes are not supported.";
 
   read_cb_ = callback;
   ReadFromDemuxerStream();
 }
 
 void FFmpegAudioDecoder::DoDecodeBuffer(const scoped_refptr<Buffer>& input) {
   DCHECK_EQ(MessageLoop::current(), message_loop_);
   DCHECK(!read_cb_.is_null());
 
+  if (!input) {
+    // DemuxeStream::Read() was aborted so we abort the decoder's pending read.
+    DeliverSamples(NULL);
+    return;
+  }
+
   // FFmpeg tends to seek Ogg audio streams in the middle of nowhere, giving us
   // a whole bunch of AV_NOPTS_VALUE packets.  Discard them until we find
   // something valid.  Refer to http://crbug.com/49709
   if (input->GetTimestamp() == kNoTimestamp() &&
       estimated_next_timestamp_ == kNoTimestamp() &&
       !input->IsEndOfStream()) {
     ReadFromDemuxerStream();
     return;
   }
 
@@ skipping 103 matching lines @@
 }
 
 void FFmpegAudioDecoder::DeliverSamples(const scoped_refptr<Buffer>& samples) {
   // Reset the callback before running to protect against reentrancy.
   ReadCB read_cb = read_cb_;
   read_cb_.Reset();
   read_cb.Run(samples);
 }
 
 }  // namespace media