Add Cast PLI support on sender side.

chrome/renderer/media/cast_transport_sender_ipc.h

Index: chrome/renderer/media/cast_transport_sender_ipc.h
diff --git a/chrome/renderer/media/cast_transport_sender_ipc.h b/chrome/renderer/media/cast_transport_sender_ipc.h
index d8bcc11b79a2df3fd0c6b3cdeef207f1e2719719..446990ba6a43a1bdff51bebc8851724b6491ff8b 100644
--- a/chrome/renderer/media/cast_transport_sender_ipc.h
+++ b/chrome/renderer/media/cast_transport_sender_ipc.h
@@ -37,11 +37,13 @@ class CastTransportSenderIPC
   void InitializeAudio(
       const media::cast::CastTransportRtpConfig& config,
       const media::cast::RtcpCastMessageCallback& cast_message_cb,
-      const media::cast::RtcpRttCallback& rtt_cb) override;
+      const media::cast::RtcpRttCallback& rtt_cb,
+      const media::cast::RtcpPliCallback& pli_cb) override;
   void InitializeVideo(
       const media::cast::CastTransportRtpConfig& config,
       const media::cast::RtcpCastMessageCallback& cast_message_cb,
-      const media::cast::RtcpRttCallback& rtt_cb) override;
+      const media::cast::RtcpRttCallback& rtt_cb,
+      const media::cast::RtcpPliCallback& pli_cb) override;
   void InsertFrame(uint32_t ssrc,
                    const media::cast::EncodedFrame& frame) override;
   void SendSenderReport(
@@ -57,6 +59,7 @@ class CastTransportSenderIPC
       uint32_t sender_ssrc,
       const media::cast::RtcpTimeData& time_data,
       const media::cast::RtcpCastMessage* cast_message,
+      const media::cast::RtcpPliMessage* pli_message,
       base::TimeDelta target_delay,
       const media::cast::ReceiverRtcpEventSubscriber::RtcpEvents* rtcp_events,
       const media::cast::RtpReceiverStatistics* rtp_receiver_statistics)
@@ -71,6 +74,7 @@ class CastTransportSenderIPC
   void OnRtt(uint32_t ssrc, base::TimeDelta rtt);
   void OnRtcpCastMessage(uint32_t ssrc,
                          const media::cast::RtcpCastMessage& cast_message);
+  void OnReceivedPli(uint32_t ssrc);
   void OnReceivedPacket(const media::cast::Packet& packet);
 
  private:
@@ -81,6 +85,7 @@ class CastTransportSenderIPC
 
     media::cast::RtcpCastMessageCallback cast_message_cb;
     media::cast::RtcpRttCallback rtt_cb;
+    media::cast::RtcpPliCallback pli_cb;
   };
 
   void Send(IPC::Message* message);