Cast: First stab at implementing adaptive latency

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 f1783166d840cab406e8602193eb2e1f4d9bbced..65eddae9aade5a918126417947cebe196c24ba28 100644
--- a/media/cast/sender/video_sender.h
+++ b/media/cast/sender/video_sender.h
@@ -25,6 +25,8 @@ namespace cast {
 class CastTransportSender;
 class VideoEncoder;
 
+typedef base::Callback<void(base::TimeDelta)> PlayoutDelayChangeCB;
+
 // Not thread safe. Only called from the main cast thread.
 // This class owns all objects related to sending video, objects that create RTP
 // packets, congestion control, video encoder, parsing and sending of
@@ -39,7 +41,8 @@ class VideoSender : public FrameSender,
               const VideoSenderConfig& video_config,
               const CreateVideoEncodeAcceleratorCallback& create_vea_cb,
               const CreateVideoEncodeMemoryCallback& create_video_encode_mem_cb,
-              CastTransportSender* const transport_sender);
+              CastTransportSender* const transport_sender,
+              const PlayoutDelayChangeCB& playout_delay_change_cb);
 
   virtual ~VideoSender();
 
@@ -77,6 +80,8 @@ class VideoSender : public FrameSender,
   // we get the same value.
   uint32 last_bitrate_;
 
+  PlayoutDelayChangeCB playout_delay_change_cb_;
+
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<VideoSender> weak_factory_;