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 18b2db13ec9fa455065ff110f9435ba4ab903379..6af7d67e774f53e538d3aa5bb2ad35eabfc05a5f 100644
--- a/media/cast/net/cast_transport_sender_impl.h
+++ b/media/cast/net/cast_transport_sender_impl.h
@@ -66,10 +66,12 @@ 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,
@@ -105,6 +107,7 @@ class CastTransportSenderImpl : public CastTransportSender {
       uint32_t sender_ssrc,
       const RtcpTimeData& time_data,
       const RtcpCastMessage* cast_message,
+      const RtcpPliMessage* pli_message,
       base::TimeDelta target_delay,
       const ReceiverRtcpEventSubscriber::RtcpEvents* rtcp_events,
       const RtpReceiverStatistics* rtp_receiver_statistics) final;