Implement adaptive target delay extension

media/cast/cast_sender.h

Index: media/cast/cast_sender.h
diff --git a/media/cast/cast_sender.h b/media/cast/cast_sender.h
index c9bad7aa1eb747af480edbca92d8e80c936ab62e..7615c28602c8f58052f4f7bf024c4eba79bc6bcc 100644
--- a/media/cast/cast_sender.h
+++ b/media/cast/cast_sender.h
@@ -86,6 +86,11 @@ class CastSender {
       const CastInitializationCallback& cast_initialization_cb,
       const CreateVideoEncodeAcceleratorCallback& create_vea_cb,
       const CreateVideoEncodeMemoryCallback& create_video_encode_mem_cb) = 0;
+
+  // Change the target delay. This is only valid if the receiver
+  // supports the "adaptive_target_delay" rtp extension.
+  virtual void SetTargetPlayoutDelay(
+      base::TimeDelta new_target_playout_delay) = 0;
 };
 
 }  // namespace cast