[Cast] Limit frames in flight by duration, and not by number of frames.

media/cast/net/cast_transport_config.h

Index: media/cast/net/cast_transport_config.h
diff --git a/media/cast/net/cast_transport_config.h b/media/cast/net/cast_transport_config.h
index dcfd133bd088fefbdcd553a2471094039dc8f763..c5da103acfba41d028be24636e280d9dbda03034 100644
--- a/media/cast/net/cast_transport_config.h
+++ b/media/cast/net/cast_transport_config.h
@@ -41,10 +41,6 @@ struct CastTransportRtpConfig {
   // RTP payload type enum: Specifies the type/encoding of frame data.
   int rtp_payload_type;
 
-  // The number of most-recent frames that must be stored in the transport
-  // layer, to facilitate re-transmissions.
-  int stored_frames;
-
   // The AES crypto key and initialization vector.  Each of these strings
   // contains the data in binary form, of size kAesKeySize.  If they are empty
   // strings, crypto is not being used.