Implement adaptive target delay extension

media/cast/cast_sender_impl.cc

Index: media/cast/cast_sender_impl.cc
diff --git a/media/cast/cast_sender_impl.cc b/media/cast/cast_sender_impl.cc
index 9a4ef3105a5a1f3314f4a4671836aaf59a52acfe..c70b51812dcb8a5273be00dcb9a7f17476c1a60e 100644
--- a/media/cast/cast_sender_impl.cc
+++ b/media/cast/cast_sender_impl.cc
@@ -150,5 +150,15 @@ scoped_refptr<VideoFrameInput> CastSenderImpl::video_frame_input() {
   return video_frame_input_;
 }
 
+void CastSenderImpl::SetTargetPlayoutDelay(
+    base::TimeDelta new_target_playout_delay) {
+  if (audio_sender_) {
+    audio_sender_->SetTargetPlayoutDelay(new_target_playout_delay);

[Alpha Left Google, 2014/08/20 20:17:05]

What happens if we:

1. InitializeVideo()
2. SetTargetPlayoutDelay()
3. InitializeAudio()

Then the target delay for audio and video would be different.

[hubbe, 2014/08/20 21:42:01]

Depends on if (3) uses the same playout delay as (1) or (2).
A sane person would set the playout delay in (3) to the same as (2), which would
do what you want.

[Alpha Left Google, 2014/08/20 21:56:37]

When InitializeAudio() or InitializeVideo() is called the parameters are usually
the default values. For example these APIs are driven from the extension and
things can go wrong. I suggest we have a DCHECK or LOG in both InitializeAudio()
and InitializeVideo() to check the target delay matches the other stream.

[hubbe, 2014/08/20 22:46:07]

Done.

+  }
+  if (video_sender_) {
+    video_sender_->SetTargetPlayoutDelay(new_target_playout_delay);
+  }
+}
+
 }  // namespace cast
 }  // namespace media