Enable transport seq num extension on receive channel to suppress log warning.

webrtc/voice_engine/channel.cc

Index: webrtc/voice_engine/channel.cc
diff --git a/webrtc/voice_engine/channel.cc b/webrtc/voice_engine/channel.cc
index b1b55e8accd9e3d4bf2edafef8ee1c36cb2a0e9e..01d2605dc9b8cb8ed8c0dbe26c709beb70cd99bf 100644
--- a/webrtc/voice_engine/channel.cc
+++ b/webrtc/voice_engine/channel.cc
@@ -2923,6 +2923,14 @@ void Channel::EnableSendTransportSequenceNumber(int id) {
   RTC_DCHECK_EQ(0, ret);
 }
 
+void Channel::EnableReceiveTransportSequenceNumber(int id) {
+  rtp_header_parser_->DeregisterRtpHeaderExtension(
+      kRtpExtensionTransportSequenceNumber);
+  bool ret = rtp_header_parser_->RegisterRtpHeaderExtension(
+      kRtpExtensionTransportSequenceNumber, id);
+  RTC_DCHECK(ret);
+}
+
 void Channel::SetCongestionControlObjects(
     RtpPacketSender* rtp_packet_sender,
     TransportFeedbackObserver* transport_feedback_observer,