MediaStream audio: Refactor 3 separate "glue" implementations into one.

content/renderer/media/media_stream_center.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/media_stream_center.h"
 
 #include <stddef.h>
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "content/common/media/media_stream_messages.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/renderer/media_stream_audio_sink.h"
 #include "content/public/renderer/render_thread.h"
 #include "content/renderer/media/media_stream.h"
 #include "content/renderer/media/media_stream_audio_track.h"
 #include "content/renderer/media/media_stream_source.h"
 #include "content/renderer/media/media_stream_video_source.h"
 #include "content/renderer/media/media_stream_video_track.h"
+#include "content/renderer/media/webaudio_media_stream_source.h"
 #include "content/renderer/media/webrtc/peer_connection_dependency_factory.h"
 #include "content/renderer/media/webrtc_local_audio_source_provider.h"
 #include "third_party/WebKit/public/platform/WebMediaConstraints.h"
 #include "third_party/WebKit/public/platform/WebMediaStream.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamCenterClient.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamTrackSourcesRequest.h"
 #include "third_party/WebKit/public/platform/WebSourceInfo.h"
 #include "third_party/WebKit/public/platform/WebVector.h"
 #include "third_party/WebKit/public/web/WebFrame.h"
 
 using blink::WebFrame;
 using blink::WebView;
 
 namespace content {
 
 namespace {
 
 void CreateNativeAudioMediaStreamTrack(
     const blink::WebMediaStreamTrack& track,
     PeerConnectionDependencyFactory* factory) {

[perkj_chrome, 2016/04/08 14:05:42]

please remove |factory| I think this might be the last dependency in this class.

[miu, 2016/04/19 00:40:22]

Done.  Yes it is!  :)

I've removed |rtc_factory_| from MediaStreamCenter, but I added a TODO to remove
the unnecessary ctor args in a follow-up change since I didn't want this change
to spread-out into even more files.  ;)

-  DCHECK(!MediaStreamAudioTrack::From(track));
   blink::WebMediaStreamSource source = track.source();
-  DCHECK_EQ(source.getType(), blink::WebMediaStreamSource::TypeAudio);
-  if (source.remote()) {
-    factory->CreateRemoteAudioTrack(track);
-  } else {
-    factory->CreateLocalAudioTrack(track);
+  MediaStreamAudioSource* media_stream_source =
+      MediaStreamAudioSource::From(source);
+
+  // At this point, a MediaStreamAudioSource instance must exist.  The one
+  // exception is when a WebAudio destination node is acting as a source of
+  // audio.
+  //
+  // TODO(miu): This needs to be moved to an appropriate location.  A WebAudio
+  // source should have been created before this method was called so that this
+  // special case code isn't needed here.
+  if (!media_stream_source && source.requiresAudioConsumer()) {
+    DVLOG(1) << "Creating WebAudio media stream source.";
+    media_stream_source = new WebAudioMediaStreamSource(&source);
+    source.setExtraData(media_stream_source);  // Takes ownership.
   }
+
+  if (media_stream_source)
+    media_stream_source->ConnectToTrack(track);
+  else
+    LOG(DFATAL) << "WebMediaStreamSource missing its MediaStreamAudioSource.";
 }
 
 void CreateNativeVideoMediaStreamTrack(
     const blink::WebMediaStreamTrack& track) {
   DCHECK(track.getExtraData() == NULL);
   blink::WebMediaStreamSource source = track.source();
   DCHECK_EQ(source.getType(), blink::WebMediaStreamSource::TypeVideo);
   MediaStreamVideoSource* native_source =
       MediaStreamVideoSource::GetVideoSource(source);
   DCHECK(native_source);
@@ skipping 24 matching lines @@
     case blink::WebMediaStreamSource::TypeVideo:
       CreateNativeVideoMediaStreamTrack(track);
       break;
   }
 }
 
 }  // namespace
 
 MediaStreamCenter::MediaStreamCenter(blink::WebMediaStreamCenterClient* client,
                                      PeerConnectionDependencyFactory* factory)
     : rtc_factory_(factory) {}

[perkj_chrome, 2016/04/08 14:05:42]

please remove

[miu, 2016/04/19 00:40:22]

Done.

 
 MediaStreamCenter::~MediaStreamCenter() {}
 
 void MediaStreamCenter::didCreateMediaStreamTrack(
     const blink::WebMediaStreamTrack& track) {
   DVLOG(1) << "MediaStreamCenter::didCreateMediaStreamTrack";
   CreateNativeMediaStreamTrack(track, rtc_factory_);
 }
 
 void MediaStreamCenter::didEnableMediaStreamTrack(
@@ skipping 78 matching lines @@
 
 bool MediaStreamCenter::didRemoveMediaStreamTrack(
     const blink::WebMediaStream& stream,
     const blink::WebMediaStreamTrack& track) {
   DVLOG(1) << "MediaStreamCenter::didRemoveMediaStreamTrack";
   MediaStream* native_stream = MediaStream::GetMediaStream(stream);
   return native_stream->RemoveTrack(track);
 }
 
 }  // namespace content