Implements MediaStreamVideoSource.

content/renderer/media/media_stream_video_source.cc

 // Copyright 2014 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_video_source.h"
 
 #include "base/logging.h"
 #include "content/public/renderer/media_stream_video_sink.h"
 
 namespace content {
 
+MediaStreamVideoSource::MediaStreamVideoSource()
+    : factory_(NULL) {}
+
 void MediaStreamVideoSource::AddTrack(
     const blink::WebMediaStreamTrack& track,

[Peng, 2014/01/09 15:32:55]

If the video track has been connected to a video source (maybe a webcam), what
will happen?

[Ronghua Wu (Left Chromium), 2014/01/09 16:50:06]

I've not decided yet. Open to suggestion. Either the new source overrides the
original source or just return an error. A track can only have one source at a
time.

[Peng, 2014/01/09 19:29:46]

IMHO, supporting changing video source in a track is not a good idea. Not sure
if blink::WebMediaStreamTrack supports it. It may have some unexpected problems.
I remember MediaStream supports adding and removing tracks. So if we want to
change a video source, we can always remove old track which contains the video
source from MediaStream and add a new track with the new video source.


BTW, I still don't know how to create an empty WebMediaStreamTrack which can be
used here and be passed to JS. If this class could have a helper function which
can create a WebMediaStreamTrack from a MediaStreamVideoSource, it will be
great. Thanks.

     const blink::WebMediaConstraints& constraints) {

[Peng, 2014/01/09 15:32:55]

Does it allow adding a track more than once? maybe with different constraints?

[Ronghua Wu (Left Chromium), 2014/01/09 16:50:06]

A track can update its constraints. So I think what we need here is an
ApplyConstraints interface. Thanks for pointing out.

http://dev.w3.org/2011/webrtc/editor/getusermedia.html#widl-Constrainable-app...

-  // TODO(ronghuawu): Put |track| in the registered tracks list. Will later
-  // deliver frames to it according to |constraints|.
+  WebRtcVideoSourceAdapter* adapter =
+      new WebRtcVideoSourceAdapter(track, constraints, factory_);
+  if (!adapter->Init()) {
+    return;
+  }
+  adapters_.push_back(adapter);
 }
 
 void MediaStreamVideoSource::RemoveTrack(
     const blink::WebMediaStreamTrack& track) {
-  // TODO(ronghuawu): Remove |track| from the list, i.e. will stop delivering
-  // frame to |track|.
+  for (WebRtcVideoSourceAdapters::iterator iter = adapters_.begin();
+       iter != adapters_.end(); ++iter) {
+    if (track.id() == (*iter)->track().id()) {
+      adapters_.erase(iter);
+      break;
+    }
+  }
 }
 
 void MediaStreamVideoSource::SetReadyState(
     blink::WebMediaStreamSource::ReadyState state) {
   // TODO(ronghuawu): Sets WebMediaStreamSource's ready state and notifies the
   // ready state to all registered tracks.
 }
 
 void MediaStreamVideoSource::DeliverVideoFrame(
     const scoped_refptr<media::VideoFrame>& frame) {
   // TODO(ronghuawu): Deliver |frame| to all the registered tracks.
 }
 
 MediaStreamVideoSource::~MediaStreamVideoSource() {
+  for (WebRtcVideoSourceAdapters::iterator iter = adapters_.begin();
+       iter != adapters_.end(); ++iter) {
+    delete *iter;
+  }
+}
+
+void MediaStreamVideoSource::SetMsFactory(
+    MediaStreamDependencyFactory* factory) {
+  factory_ = factory;
 }
 
 }  // namespace content