Add VideoTrackSource implementation.

webrtc/api/mediastreaminterface.h

Index: webrtc/api/mediastreaminterface.h
diff --git a/webrtc/api/mediastreaminterface.h b/webrtc/api/mediastreaminterface.h
index c9ce4a5a7b49d7bf26a9e5e07677228a3651cc98..0fe29a7de644ba7dd2febea6a271217accc74e20 100644
--- a/webrtc/api/mediastreaminterface.h
+++ b/webrtc/api/mediastreaminterface.h
@@ -139,7 +139,8 @@ class VideoTrackSourceInterface
   virtual void Stop() = 0;
   virtual void Restart() = 0;
 
-  virtual const cricket::VideoOptions* options() const = 0;
+  virtual bool is_screencast() const = 0;
+  virtual bool needs_denoising() const = 0;

[pthatcher1, 2016/03/08 21:27:31]

Can you put a comment in here like:

// Indicates that parameters suitable for screencasts should be automatically
applied to RtpSenders.  
// TODO: Remove these once all known applications have moved to explicitly
setting suitable parameters for screencasts and dont' need this implicit
behavior.

and

// Indicates that the encoder should denoise the video before encoding it.  
// TODO: Remove this once denoising is done by the source, and not by the
encoder.

[perkj_webrtc, 2016/03/08 22:23:57]

Done.

 
  protected:
   virtual ~VideoTrackSourceInterface() {}