Forward the SignalFirstPacketReceived to RtpReceiver.

webrtc/api/webrtcsession.cc

Index: webrtc/api/webrtcsession.cc
diff --git a/webrtc/api/webrtcsession.cc b/webrtc/api/webrtcsession.cc
index 80352cf83246f3ff5f42a4bfa4be64f496a5e153..70571db0f34f2874444deef56b49dd7027b77878 100644
--- a/webrtc/api/webrtcsession.cc
+++ b/webrtc/api/webrtcsession.cc
@@ -1817,6 +1817,8 @@ bool WebRtcSession::CreateVoiceChannel(const cricket::ContentInfo* content,
 
   voice_channel_->SignalDtlsSetupFailure.connect(
       this, &WebRtcSession::OnDtlsSetupFailure);
+  voice_channel_->SignalFirstPacketReceived.connect(
+      this, &WebRtcSession::OnChannelFirstPacketReceived);
 
   SignalVoiceChannelCreated();
   voice_channel_->SignalSentPacket.connect(this,
@@ -1840,6 +1842,8 @@ bool WebRtcSession::CreateVideoChannel(const cricket::ContentInfo* content,
   }
   video_channel_->SignalDtlsSetupFailure.connect(
       this, &WebRtcSession::OnDtlsSetupFailure);
+  video_channel_->SignalFirstPacketReceived.connect(
+      this, &WebRtcSession::OnChannelFirstPacketReceived);
 
   SignalVideoChannelCreated();
   video_channel_->SignalSentPacket.connect(this,
@@ -1881,6 +1885,21 @@ void WebRtcSession::OnDtlsSetupFailure(cricket::BaseChannel*, bool rtcp) {
            rtcp ? kDtlsSetupFailureRtcp : kDtlsSetupFailureRtp);
 }
 
+void WebRtcSession::OnChannelFirstPacketReceived(
+    cricket::BaseChannel* channel) {
+  ASSERT(signaling_thread()->IsCurrent());
+
+  if (!has_received_audio_packet_ &&
+      channel->content_name() == cricket::CN_AUDIO) {

[pthatcher2, 2016/05/20 20:23:14]

We should use the media type, not the content name.

[zhihuang1, 2016/05/24 01:01:44]

Done.

+    has_received_audio_packet_ = true;
+    SignalFirstAudioPacketReceived();
+  } else if (!has_received_video_packet_ &&
+             channel->content_name() == cricket::CN_VIDEO) {
+    has_received_video_packet_ = true;
+    SignalFirstVideoPacketReceived();
+  }
+}
+
 void WebRtcSession::OnDataChannelMessageReceived(
     cricket::DataChannel* channel,
     const cricket::ReceiveDataParams& params,