Add Cast PLI support on sender side.

media/cast/net/cast_transport_sender_impl.h

Index: media/cast/net/cast_transport_sender_impl.h
diff --git a/media/cast/net/cast_transport_sender_impl.h b/media/cast/net/cast_transport_sender_impl.h
index 5feebc62404c31effa1ced780c7e21af4667b71b..6168979bb560ed7dc00b5f8aca5c24fc9952a224 100644
--- a/media/cast/net/cast_transport_sender_impl.h
+++ b/media/cast/net/cast_transport_sender_impl.h
@@ -67,10 +67,12 @@ class CastTransportSenderImpl : public CastTransportSender {
   // CastTransportSender implementation.
   void InitializeAudio(const CastTransportRtpConfig& config,
                        const RtcpCastMessageCallback& cast_message_cb,
-                       const RtcpRttCallback& rtt_cb) final;
+                       const RtcpRttCallback& rtt_cb,
+                       const RtcpPliCallback& pli_cb) final;
   void InitializeVideo(const CastTransportRtpConfig& config,
                        const RtcpCastMessageCallback& cast_message_cb,
-                       const RtcpRttCallback& rtt_cb) final;
+                       const RtcpRttCallback& rtt_cb,
+                       const RtcpPliCallback& pli_cb) final;
   void InsertFrame(uint32_t ssrc, const EncodedFrame& frame) final;
 
   void SendSenderReport(uint32_t ssrc,
@@ -107,6 +109,7 @@ class CastTransportSenderImpl : public CastTransportSender {
                                         const RtcpTimeData& time_data) final;
   void AddCastFeedback(const RtcpCastMessage& cast_message,
                        base::TimeDelta target_delay) final;
+  void AddPli(const RtcpPliMessage& pli_message) final;

[dcheng, 2016/03/16 01:39:24]

Maybe just mark the entire class final?

[xjz, 2016/03/16 17:12:13]

Marked the class final. Code style still requires marking overriding method with
"override" or "final", which ensures that the function is virtual.

   void AddRtcpEvents(
       const ReceiverRtcpEventSubscriber::RtcpEvents& rtcp_events) final;
   void AddRtpReceiverReport(