Revert of MediaStream audio object graph untangling and clean-ups.

content/renderer/media/audio_track_recorder.cc

 // Copyright 2015 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 "content/renderer/media/audio_track_recorder.h"
 
 #include <stdint.h>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/stl_util.h"
-#include "content/renderer/media/media_stream_audio_track.h"
 #include "media/audio/audio_parameters.h"
 #include "media/base/audio_bus.h"
 #include "media/base/audio_converter.h"
 #include "media/base/audio_fifo.h"
 #include "media/base/bind_to_current_loop.h"
 #include "third_party/opus/src/include/opus.h"
 
 // Note that this code follows the Chrome media convention of defining a "frame"
 // as "one multi-channel sample" as opposed to another common definition meaning
 // "a chunk of samples". Here this second definition of "frame" is called a
@@ skipping 264 matching lines @@
 AudioTrackRecorder::AudioTrackRecorder(
     const blink::WebMediaStreamTrack& track,
     const OnEncodedAudioCB& on_encoded_audio_cb,
     int32_t bits_per_second)
     : track_(track),
       encoder_(new AudioEncoder(media::BindToCurrentLoop(on_encoded_audio_cb),
                                 bits_per_second)),
       encoder_thread_("AudioEncoderThread") {
   DCHECK(main_render_thread_checker_.CalledOnValidThread());
   DCHECK(!track_.isNull());
-  DCHECK(MediaStreamAudioTrack::From(track_));
+  DCHECK(track_.extraData());
 
   // Start the |encoder_thread_|. From this point on, |encoder_| should work
   // only on |encoder_thread_|, as enforced by DCHECKs.
   DCHECK(!encoder_thread_.IsRunning());
   encoder_thread_.Start();
 
   // Connect the source provider to the track as a sink.
   MediaStreamAudioSink::AddToAudioTrack(this, track_);
 }
 
@@ skipping 21 matching lines @@
   scoped_ptr<media::AudioBus> audio_data =
       media::AudioBus::Create(audio_bus.channels(), audio_bus.frames());
   audio_bus.CopyTo(audio_data.get());
 
   encoder_thread_.task_runner()->PostTask(
       FROM_HERE, base::Bind(&AudioEncoder::EncodeAudio, encoder_,
                             base::Passed(&audio_data), capture_time));
 }
 
 }  // namespace content