Reland "Update rtt on audio only calls".

webrtc/audio/audio_send_stream.cc

Index: webrtc/audio/audio_send_stream.cc
diff --git a/webrtc/audio/audio_send_stream.cc b/webrtc/audio/audio_send_stream.cc
index 29789aab7cadeb141e9f67640a647f0e1e377fc6..aff605fe6a6845b995fd2082d458d8e5b9f45f4c 100644
--- a/webrtc/audio/audio_send_stream.cc
+++ b/webrtc/audio/audio_send_stream.cc
@@ -48,7 +48,8 @@ AudioSendStream::AudioSendStream(
     PacketRouter* packet_router,
     CongestionController* congestion_controller,
     BitrateAllocator* bitrate_allocator,
-    RtcEventLog* event_log)
+    RtcEventLog* event_log,
+    RtcpRttStats* rtcp_rtt_stats)
     : worker_queue_(worker_queue),
       config_(config),
       audio_state_(audio_state),
@@ -61,6 +62,7 @@ AudioSendStream::AudioSendStream(
   VoiceEngineImpl* voe_impl = static_cast<VoiceEngineImpl*>(voice_engine());
   channel_proxy_ = voe_impl->GetChannelProxy(config_.voe_channel_id);
   channel_proxy_->SetRtcEventLog(event_log);
+  channel_proxy_->SetRtcpRttStats(rtcp_rtt_stats);
   channel_proxy_->RegisterSenderCongestionControlObjects(
       congestion_controller->pacer(),
       congestion_controller->GetTransportFeedbackObserver(), packet_router);
@@ -94,6 +96,7 @@ AudioSendStream::~AudioSendStream() {
   channel_proxy_->DeRegisterExternalTransport();
   channel_proxy_->ResetCongestionControlObjects();
   channel_proxy_->SetRtcEventLog(nullptr);
+  channel_proxy_->SetRtcpRttStats(nullptr);
 }
 
 void AudioSendStream::Start() {