MediaStream audio object graph untangling and clean-ups.

content/renderer/media/user_media_client_impl.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/user_media_client_impl.h"
 
 #include <stddef.h>
 
 #include <utility>
 #include <vector>
@@ skipping 1032 matching lines @@
 
 UserMediaClientImpl::UserMediaRequestInfo::~UserMediaRequestInfo() {
   DVLOG(1) << "~UserMediaRequestInfo";
 }
 
 void UserMediaClientImpl::UserMediaRequestInfo::StartAudioTrack(
     const blink::WebMediaStreamTrack& track,
     const blink::WebMediaConstraints& constraints) {
   DCHECK(track.source().type() == blink::WebMediaStreamSource::TypeAudio);
   MediaStreamAudioSource* native_source =
-      static_cast <MediaStreamAudioSource*>(track.source().extraData());
+      MediaStreamAudioSource::From(track.source());
   DCHECK(native_source);
 
   sources_.push_back(track.source());
   sources_waiting_for_callback_.push_back(native_source);
   native_source->AddTrack(
       track, constraints, base::Bind(
           &UserMediaClientImpl::UserMediaRequestInfo::OnTrackStarted,
           AsWeakPtr()));
 }
 
@@ skipping 69 matching lines @@
       return;
     }
   }
 }
 
 bool UserMediaClientImpl::UserMediaRequestInfo::HasPendingSources() const {
   return !sources_waiting_for_callback_.empty();
 }
 
 }  // namespace content