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

content/renderer/media/track_audio_renderer.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 "content/renderer/media/track_audio_renderer.h"
 
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/synchronization/lock.h"
@@ skipping 113 matching lines @@
     : audio_track_(audio_track),
       playout_render_frame_id_(playout_render_frame_id),
       session_id_(session_id),
       task_runner_(base::ThreadTaskRunnerHandle::Get()),
       num_samples_rendered_(0),
       playing_(false),
       output_device_id_(device_id),
       security_origin_(security_origin),
       volume_(0.0),
       sink_started_(false) {
-  DCHECK(MediaStreamAudioTrack::From(audio_track_));
+  DCHECK(MediaStreamAudioTrack::GetTrack(audio_track_));
   DVLOG(1) << "TrackAudioRenderer::TrackAudioRenderer()";
 }
 
 TrackAudioRenderer::~TrackAudioRenderer() {
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(!sink_.get());
   DVLOG(1) << "TrackAudioRenderer::~TrackAudioRenderer()";
 }
 
 void TrackAudioRenderer::Start() {
@@ skipping 85 matching lines @@
   if (source_params_.IsValid()) {
     return ComputeTotalElapsedRenderTime(prior_elapsed_render_time_,
                                          num_samples_rendered_,
                                          source_params_.sample_rate());
   }
   return prior_elapsed_render_time_;
 }
 
 bool TrackAudioRenderer::IsLocalRenderer() const {
   DCHECK(task_runner_->BelongsToCurrentThread());
-  return MediaStreamAudioTrack::From(audio_track_)->is_local_track();
+  return MediaStreamAudioTrack::GetTrack(audio_track_)->is_local_track();
 }
 
 void TrackAudioRenderer::SwitchOutputDevice(
     const std::string& device_id,
     const url::Origin& security_origin,
     const media::SwitchOutputDeviceCB& callback) {
   DVLOG(1) << "TrackAudioRenderer::SwitchOutputDevice()";
   DCHECK(task_runner_->BelongsToCurrentThread());
 
   {
@@ skipping 137 matching lines @@
   if (source_params_.IsValid()) {
     prior_elapsed_render_time_ =
         ComputeTotalElapsedRenderTime(prior_elapsed_render_time_,
                                       num_samples_rendered_,
                                       source_params_.sample_rate());
     num_samples_rendered_ = 0;
   }
 }
 
 }  // namespace content