cast: Support for low-latency interactive mode

media/cast/sender/video_sender.h

Index: media/cast/sender/video_sender.h
diff --git a/media/cast/sender/video_sender.h b/media/cast/sender/video_sender.h
index ab31e7b9b3562185474864c02c47a591fff15780..b47c125ad9efb6f122c40e4434a0977eb4cc8823 100644
--- a/media/cast/sender/video_sender.h
+++ b/media/cast/sender/video_sender.h
@@ -98,6 +98,9 @@ class VideoSender : public FrameSender,
 
   PlayoutDelayChangeCB playout_delay_change_cb_;
 
+  // Interactive mode as indicated by the web content capture logic.

[miu, 2015/12/03 21:26:23]

This concepts mentioned in this comment is an abstraction violation.  Thinking
about what this bool controls in VideoSender, you could call it:
low_latency_mode_;

[Irfan, 2015/12/04 22:45:37]

Done.

+  bool interactive_mode_;
+
   // The video encoder's performance metrics as of the last call to
   // OnEncodedVideoFrame().  See header file comments for SenderEncodedFrame for
   // an explanation of these values.