Make the audio channel communicate network state changes to the call.

webrtc/media/engine/webrtcvoiceengine.cc

Index: webrtc/media/engine/webrtcvoiceengine.cc
diff --git a/webrtc/media/engine/webrtcvoiceengine.cc b/webrtc/media/engine/webrtcvoiceengine.cc
index 4f6ae434c70d067185dd46b702010a08cf8fb78d..fbaab675ec58d6a78b60cf9ac62e7c93955047ca 100644
--- a/webrtc/media/engine/webrtcvoiceengine.cc
+++ b/webrtc/media/engine/webrtcvoiceengine.cc
@@ -2419,6 +2419,14 @@ bool WebRtcVoiceMediaChannel::SetSendBitrateInternal(int bps) {
   }
 }
 
+void WebRtcVoiceMediaChannel::OnReadyToSend(bool ready) {
+  RTC_DCHECK(worker_thread_checker_.CalledOnValidThread());
+  LOG(LS_VERBOSE) << "OnReadyToSend: " << (ready ? "Ready." : "Not ready.");
+  call_->SignalChannelNetworkState(
+      webrtc::MediaType::AUDIO,
+      ready ? webrtc::kNetworkUp : webrtc::kNetworkDown);
+}
+
 bool WebRtcVoiceMediaChannel::GetStats(VoiceMediaInfo* info) {
   TRACE_EVENT0("webrtc", "WebRtcVoiceMediaChannel::GetStats");
   RTC_DCHECK(worker_thread_checker_.CalledOnValidThread());