Attach TransportFeedbackPacketLossTracker to ANA (PLR only)

webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h

Index: webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
diff --git a/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h b/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
index ab9fc401674140a65cdb99066a1de40cfea47e08..012b978e8167198693754b2eff46c45c612fb44c 100644
--- a/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
+++ b/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
@@ -343,7 +343,8 @@ class TransportFeedbackObserver {
   virtual ~TransportFeedbackObserver() {}
 
   // Note: Transport-wide sequence number as sequence number.
-  virtual void AddPacket(uint16_t sequence_number,
+  virtual void AddPacket(uint32_t ssrc,
+                         uint16_t sequence_number,
                          size_t length,
                          const PacedPacketInfo& pacing_info) = 0;
 
@@ -352,6 +353,15 @@ class TransportFeedbackObserver {
   virtual std::vector<PacketFeedback> GetTransportFeedbackVector() const = 0;
 };
 
+class PacketFeedbackObserver {
+ public:
+  virtual ~PacketFeedbackObserver() = default;
+
+  virtual void OnPacketAdded(uint32_t ssrc, uint16_t seq_num) = 0;
+  virtual void OnPacketFeedbackVector(
+      const std::vector<PacketFeedback>& packet_feedback_vector) = 0;
+};
+
 class RtcpRttStats {
  public:
   virtual void OnRttUpdate(int64_t rtt) = 0;