Add Cast PLI support on sender side.

media/cast/net/rtcp/receiver_rtcp_session.cc

Index: media/cast/net/rtcp/receiver_rtcp_session.cc
diff --git a/media/cast/net/rtcp/receiver_rtcp_session.cc b/media/cast/net/rtcp/receiver_rtcp_session.cc
index ba917da6155be5ef2728e7f403a4dad78aba6759..2e15955fe4a95a046a061ef69fd8fccd355f4c75 100644
--- a/media/cast/net/rtcp/receiver_rtcp_session.cc
+++ b/media/cast/net/rtcp/receiver_rtcp_session.cc
@@ -104,9 +104,10 @@ void ReceiverRtcpSession::SendRtcpReport(
     const RtpReceiverStatistics* rtp_receiver_statistics) const {
   RtcpReportBlock report_block;
   RtcpReceiverReferenceTimeReport rrtr;
-  rrtr.ntp_seconds = time_data.ntp_seconds;
-  rrtr.ntp_fraction = time_data.ntp_fraction;
-
+  if ((!cast_message) || (!cast_message->picture_loss_indicator)) {
+    rrtr.ntp_seconds = time_data.ntp_seconds;
+    rrtr.ntp_fraction = time_data.ntp_fraction;
+  }
   if (rtp_receiver_statistics) {
     report_block.remote_ssrc = 0;            // Not needed to set send side.
     report_block.media_ssrc = remote_ssrc_;  // SSRC of the RTP packet sender.
@@ -130,9 +131,12 @@ void ReceiverRtcpSession::SendRtcpReport(
   }
   RtcpBuilder rtcp_builder(local_ssrc_);
   packet_sender_->SendRtcpPacket(
-      local_ssrc_, rtcp_builder.BuildRtcpFromReceiver(
-                       rtp_receiver_statistics ? &report_block : NULL, &rrtr,
-                       cast_message, rtcp_events, target_delay));
+      local_ssrc_,
+      rtcp_builder.BuildRtcpFromReceiver(
+          rtp_receiver_statistics ? &report_block : nullptr,
+          (cast_message && cast_message->picture_loss_indicator) ? nullptr

[miu, 2016/02/26 23:36:06]

Separate argument for PLI here too.

Also, it seems like you can send the RRTR along with the PLI, if |cast_message|
was not null.  See comments in rtcp_builder.cc.

[xjz, 2016/02/27 05:53:32]

Done.

+                                                                 : &rrtr,
+          cast_message, rtcp_events, target_delay));
 }
 
 void ReceiverRtcpSession::OnReceivedLipSyncInfo(RtpTimeTicks rtp_timestamp,