Replace SetCapturer and SetCaptureDevice by SetSource.

webrtc/api/videotracksource.cc

Index: webrtc/api/videotracksource.cc
diff --git a/webrtc/api/videotracksource.cc b/webrtc/api/videotracksource.cc
index f8212d7a70cab20cfce2d4dc5349bb172b06cc4f..2a9e7e5a17b7f2137fdc612a8d41e7e4fb7eda54 100644
--- a/webrtc/api/videotracksource.cc
+++ b/webrtc/api/videotracksource.cc
@@ -57,4 +57,10 @@ void VideoTrackSource::RemoveSink(
                 source_, sink));
 }
 
+void VideoTrackSource::GetInfo(rtc::VideoSourceInfo *info) {
+  if (source_)
+    source_->GetInfo(info);

[perkj_webrtc, 2016/03/20 15:01:46]

Humm. This looks like a potential race with OnSourceDestroyed. 
Actually - you call GetInfo on the worker thread from webrtcvideoengine2.
Everything else in this class is called on the signaling thread. 

[nisse-webrtc, 2016/03/23 14:07:02]

I'd need some guidance on how to get the threading right. As for
OnSourceDestroyed, it seems like calling GetInfo at the same time (or after) the
source is destroyed is a plain use-after-free. It should be invalid to destroy a
source while it is registered with VideoMediaChannel->SetSource, right?

[perkj_webrtc, 2016/03/24 11:02:50]

That is correct. And should in practice never happen since it means we have a
bug else where. Maybe we can just document that somehow. 

+}
+
+
 }  //  namespace webrtc