cast: Support for low-latency interactive mode

media/cast/sender/frame_sender.cc

Index: media/cast/sender/frame_sender.cc
diff --git a/media/cast/sender/frame_sender.cc b/media/cast/sender/frame_sender.cc
index 44f505e8c26c03e3d9d6864fd5fa2fcc11296c45..830f1758882fa575630b1f6cf302d299fe678839 100644
--- a/media/cast/sender/frame_sender.cc
+++ b/media/cast/sender/frame_sender.cc
@@ -4,6 +4,9 @@
 
 #include "media/cast/sender/frame_sender.h"
 
+#include <algorithm>
+#include <vector>
+
 #include "base/trace_event/trace_event.h"
 #include "media/cast/cast_defines.h"
 #include "media/cast/constants.h"
@@ -37,8 +40,7 @@ FrameSender::FrameSender(scoped_refptr<CastEnvironment> cast_environment,
     : cast_environment_(cast_environment),
       transport_sender_(transport_sender),
       ssrc_(ssrc),
-      min_playout_delay_(min_playout_delay == base::TimeDelta() ?
-                         max_playout_delay : min_playout_delay),
+      min_playout_delay_(min_playout_delay),

[miu, 2015/12/01 21:15:27]

Sanity-check: Can min_playout_delay ever be zero?  Should we at least do
something like this here: std::max(50 milliseconds, min_playout_delay)

[Irfan, 2015/12/02 22:32:44]

I have gone to previous logic since if there is no min provided, I want to
disable the dynamic playout delay adjustment.

If there is just max provided (400) like now, we will basically end up with
fixed playout delay at all time.

       max_playout_delay_(max_playout_delay),
       send_target_playout_delay_(false),
       max_frame_rate_(max_frame_rate),
@@ -53,7 +55,8 @@ FrameSender::FrameSender(scoped_refptr<CastEnvironment> cast_environment,
   DCHECK(transport_sender_);
   DCHECK_GT(rtp_timebase_, 0);
   DCHECK(congestion_control_);
-  SetTargetPlayoutDelay(min_playout_delay_);
+  SetTargetPlayoutDelay(
+      base::TimeDelta::FromMilliseconds(kNonInteractiveModeStartPlayoutTimeMs));
   send_target_playout_delay_ = false;
   memset(frame_rtp_timestamps_, 0, sizeof(frame_rtp_timestamps_));
 }