[Cast] In Audio/VideoSender, drop frames when too-long a duration is in-flight.

media/cast/sender/frame_sender.h

Index: media/cast/sender/frame_sender.h
diff --git a/media/cast/sender/frame_sender.h b/media/cast/sender/frame_sender.h
index 5da3927961f7262aca2774ffd60254610c4b17b6..b6580bd180be86c374092ece4e60c253de5eef10 100644
--- a/media/cast/sender/frame_sender.h
+++ b/media/cast/sender/frame_sender.h
@@ -94,6 +94,11 @@ class FrameSender {
   // new frames shall halt.
   int max_unacked_frames_;
 
+  // Maximum difference between a new frame's RTP timestamp and the oldest
+  // unacked frame's RTP timestamp, before encoding and sending of new frames
+  // shall halt.
+  int64 max_unacked_rtp_delta_;

[hubbe, 2014/08/26 17:49:56]

Why not TimeDelta?

[miu, 2014/08/26 19:57:19]

It more convenient to have in the time calculations being done in
Audio/VideoSender::ShouldDropNextFrame().  Slightly less math since both
AudioSender and VideoSender already store the prior frame RTP timestamps in the
frame_id_to_rtp_timestamp_ map.

[hubbe, 2014/08/26 20:54:21]

This is an odd situation. Usually you're the one who wants to use
timetick/timedelta for all time calculations....  I'm not convinced that the
convenience is worth it, it seems the code will be clearer without modular math.

[miu, 2014/08/26 23:27:16]

Done.  I rewrote it the other way.  The ShouldDropNextFrame() code was about the
same in math, but the max_unacked_rtp_delta_ field could be removed and just use
target_playout_delay_.  So, I'll admit your way is cleaner.  ;-)

+
  private:
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<FrameSender> weak_factory_;