Chrome MediaStream VideoTrack implementation.

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 <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/render_thread.h"
 #include "content/renderer/media/media_stream.h"
 #include "content/renderer/media/media_stream_dependency_factory.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 "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;
@@ skipping 11 matching lines @@
   DCHECK_EQ(source.type(), blink::WebMediaStreamSource::TypeAudio);
   factory->CreateLocalAudioTrack(track);
 }
 
 void CreateNativeVideoMediaStreamTrack(
     const blink::WebMediaStreamTrack& track,
     MediaStreamDependencyFactory* factory) {
   DCHECK(track.extraData() == NULL);
   blink::WebMediaStreamSource source = track.source();
   DCHECK_EQ(source.type(), blink::WebMediaStreamSource::TypeVideo);
-
-  if (!source.extraData()) {
+  MediaStreamVideoSource* native_source =
+      MediaStreamVideoSource::GetVideoSource(source);
+  if (!native_source) {
     // TODO(perkj): Implement support for sources from
     // remote MediaStreams.
     NOTIMPLEMENTED();
     return;
   }
-  MediaStreamTrack* native_track = new MediaStreamVideoTrack(factory);
-  native_track->SetEnabled(track.isEnabled());
-  blink::WebMediaStreamTrack writable_track(track);
-  writable_track.setExtraData(native_track);
+  MediaStreamVideoTrack::CreateVideoTrack(

[Ronghua Wu (Left Chromium), 2014/03/04 01:04:11]

I'm confused, who gets the newly created blink::WebMediaStreamTrack?

Or the return value will be the same as |track|? In which case |track| should
not be const&, i.e |track| is changed.

[perkj_chrome, 2014/03/04 10:44:51]

Good catch - right - this is wrong.... |track| has been created by blink so we
should not create a new one. Simply initialize the chrome version.

[Ronghua Wu (Left Chromium), 2014/03/04 23:50:55]

Not sure if writable_track is the common practice, but being able to change a
const& seems be strange to me.

+      native_source, source.constraints(),
+      MediaStreamVideoSource::ConstraintsCallback(), track.isEnabled(),
+      factory);
 }
 
 void CreateNativeMediaStreamTrack(const blink::WebMediaStreamTrack& track,
                                   MediaStreamDependencyFactory* factory) {
   DCHECK(!track.isNull() && !track.extraData());
   DCHECK(!track.source().isNull());
 
   switch (track.source().type()) {
     case blink::WebMediaStreamSource::TypeAudio:
       CreateNativeAudioMediaStreamTrack(track, factory);
@@ skipping 175 matching lines @@
                     device.type == MEDIA_DEVICE_AUDIO_CAPTURE
                         ? blink::WebSourceInfo::SourceKindAudio
                         : blink::WebSourceInfo::SourceKindVideo,
                     blink::WebString::fromUTF8(device.name),
                     video_facing);
   }
   request_it->second.requestSucceeded(sourceInfos);
 }
 
 }  // namespace content