[Cast] Clean-up: Move max_unacked_frames into CongestionControl.

media/cast/sender/congestion_control.h

Index: media/cast/sender/congestion_control.h
diff --git a/media/cast/sender/congestion_control.h b/media/cast/sender/congestion_control.h
index 5d1256f75a953f77900f60223055d8aa552a465c..8c3d764e20fc73f19e11936a1722066746446663 100644
--- a/media/cast/sender/congestion_control.h
+++ b/media/cast/sender/congestion_control.h
@@ -22,6 +22,9 @@ class CongestionControl {
   // Called with latest measured rtt value.
   virtual void UpdateRtt(base::TimeDelta rtt) = 0;
 
+  // Called with an updated target playout delay value.
+  virtual void UpdateTargetPlayoutDelay(base::TimeDelta delay) = 0;
+
   // Called when an encoded frame is sent to the transport.
   virtual void SendFrameToTransport(uint32 frame_id,
                                     size_t frame_size,
@@ -38,7 +41,7 @@ CongestionControl* NewAdaptiveCongestionControl(
     base::TickClock* clock,
     uint32 max_bitrate_configured,
     uint32 min_bitrate_configured,
-    size_t max_unacked_frames);
+    double max_frame_rate);
 
 CongestionControl* NewFixedCongestionControl(uint32 bitrate);