[cleanup] Remove unused fields/functions from rtcp module.

webrtc/modules/rtp_rtcp/source/rtcp_receiver.h

Index: webrtc/modules/rtp_rtcp/source/rtcp_receiver.h
diff --git a/webrtc/modules/rtp_rtcp/source/rtcp_receiver.h b/webrtc/modules/rtp_rtcp/source/rtcp_receiver.h
index 24861bd49e6aeb4963c2297b203bbdae4c550648..30677086fdd828a305cd353f54a06a7092d03251 100644
--- a/webrtc/modules/rtp_rtcp/source/rtcp_receiver.h
+++ b/webrtc/modules/rtp_rtcp/source/rtcp_receiver.h
@@ -46,12 +46,9 @@ public:
 
     void SetSsrcs(uint32_t main_ssrc,
                   const std::set<uint32_t>& registered_ssrcs);
-    void SetRelaySSRC(uint32_t ssrc);
     void SetRemoteSSRC(uint32_t ssrc);
     uint32_t RemoteSSRC() const;
 
-    uint32_t RelaySSRC() const;
-
     int32_t IncomingRTCPPacket(
         RTCPHelp::RTCPPacketInformation& rtcpPacketInformation,
         RTCPUtility::RTCPParserV2 *rtcpParser);
@@ -303,8 +300,6 @@ protected:
   ReceivedInfoMap _receivedInfoMap;
   std::map<uint32_t, RTCPUtility::RTCPCnameInformation*> _receivedCnameMap;
 
-  uint32_t _packetTimeOutMS;
-
   // The last time we received an RTCP RR.
   int64_t _lastReceivedRrMs;