Wire up RTP keep-alive in ortc api.

webrtc/call/call.cc

Index: webrtc/call/call.cc
diff --git a/webrtc/call/call.cc b/webrtc/call/call.cc
index 25dcf32a620c48965c22077d8c6d35cc3b298267..dd5ef9c7a87744cfd67a368b3f2bda719574bf78 100644
--- a/webrtc/call/call.cc
+++ b/webrtc/call/call.cc
@@ -212,6 +212,7 @@ class Call : public webrtc::Call,
 
   void OnSentPacket(const rtc::SentPacket& sent_packet) override;
 
+  bool SetRtpKeepAliveConfig(const RtpKeepAliveConfig& config) override;
 
   // Implements BitrateObserver.
   void OnNetworkChanged(uint32_t bitrate_bps,
@@ -1143,6 +1144,20 @@ void Call::OnSentPacket(const rtc::SentPacket& sent_packet) {
   transport_send_->send_side_cc()->OnSentPacket(sent_packet);
 }
 
+bool Call::SetRtpKeepAliveConfig(const RtpKeepAliveConfig& config) {
+  // Can be called by RtpTransportController not on the configuration thread.

[stefan-webrtc, 2017/08/08 08:13:06]

This comment will become confusing. Call currently has an
RtpTransportControllerSend object, which is what I'd expect that this refers to.
Should this method be added to that class instead? That way the send streams can
ask the RtpTransportControllerSend whether or not to enable keepalive. Later on,
the RtpTransportController will be responsible for RTP and also keepalive.

[sprang_webrtc, 2017/08/08 08:53:30]

OK, so this badly phrased comment referred to the RtpTransportControllerAdapter
in the ortc api, which is not quite the same.

I've updated that class to actually configure this on the configuration thread
as well. So removed comment and added back thread check.

+
+  ReadLockScoped lock(*send_crit_);
+  if (config != config_.keepalive_config &&
+      (!video_send_streams_.empty() || !audio_send_ssrcs_.empty())) {
+    LOG(LS_WARNING) << "RTP keep-alive settings cannot be altered after "
+                       "creating send streams.";
+    return false;
+  }
+  config_.keepalive_config = config;
+  return true;
+}
+
 void Call::OnNetworkChanged(uint32_t target_bitrate_bps,
                             uint8_t fraction_loss,
                             int64_t rtt_ms,