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 7a3b6fd829002b8a1d30891a02ae5e9fd71a5461..9de65abdbda8c54b6c11df136ba47fbc4562e35f 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_receiver_audio.cc
@@ -194,6 +194,10 @@ 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,