Added log messages for important call setup events: first packet sent/received

webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc b/webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc
index c4c7dbb4cd3eafaf811573115f302af8bafb84b4..d0571f085d5fe08b4a49265297bd9de17c0e8943 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc
@@ -197,6 +197,10 @@ int32_t RTPReceiverAudio::ParseRtpPacket(WebRtcRTPHeader* rtp_header,
            rtp_header->type.Audio.numEnergy);
   }
 
+  if (first_packet_received_()) {
+    LOG(LS_INFO) << "Received first audio RTP packet";
+  }
+
   return ParseAudioCodecSpecific(rtp_header,
                                  payload,
                                  payload_length,