Add PeerConnection option to enable RTX handling in the audio jitter buffer.

Bug: webrtc:10178
Change-Id: I70abce0c7b74124d2b1978d9a5eb8216b6233d1a
Reviewed-on: https://webrtc-review.googlesource.com/c/116784
Commit-Queue: Jakob Ivarsson‎ <jakobi@webrtc.org>
Reviewed-by: Minyue Li <minyue@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26203}
diff --git a/api/peerconnectioninterface.h b/api/peerconnectioninterface.h
index c2fb6a3..91d71b4 100644
--- a/api/peerconnectioninterface.h
+++ b/api/peerconnectioninterface.h
@@ -454,6 +454,10 @@
     // The minimum delay in milliseconds for the audio jitter buffer.
     int audio_jitter_buffer_min_delay_ms = 0;
 
+    // Whether the audio jitter buffer adapts the delay to retransmitted
+    // packets.
+    bool audio_jitter_buffer_enable_rtx_handling = false;
+
     // Timeout in milliseconds before an ICE candidate pair is considered to be
     // "not receiving", after which a lower priority candidate pair may be
     // selected.