Attach TransportFeedbackPacketLossTracker to ANA (PLR only)

webrtc/modules/congestion_controller/transport_feedback_adapter.h

Index: webrtc/modules/congestion_controller/transport_feedback_adapter.h
diff --git a/webrtc/modules/congestion_controller/transport_feedback_adapter.h b/webrtc/modules/congestion_controller/transport_feedback_adapter.h
index 632f125aa66019c46cbe65e89aaddcebd6b15124..47c43150834138e15683486c6a7d128dc1db5727 100644
--- a/webrtc/modules/congestion_controller/transport_feedback_adapter.h
+++ b/webrtc/modules/congestion_controller/transport_feedback_adapter.h
@@ -34,7 +34,8 @@ class TransportFeedbackAdapter : public TransportFeedbackObserver,
 
   void InitBwe();
   // Implements TransportFeedbackObserver.
-  void AddPacket(uint16_t sequence_number,
+  void AddPacket(uint32_t ssrc,
+                 uint16_t sequence_number,
                  size_t length,
                  int probe_cluster_id) override;
   void OnSentPacket(uint16_t sequence_number, int64_t send_time_ms);
@@ -54,6 +55,11 @@ class TransportFeedbackAdapter : public TransportFeedbackObserver,
 
   int64_t GetProbingIntervalMs() const;
 
+  void RegisterTransportFeedbackAdapterObserver(
+      TransportFeedbackAdapterObserver* observer);
+  void DeRegisterTransportFeedbackAdapterObserver(
+      TransportFeedbackAdapterObserver* observer);
+
  private:
   std::vector<PacketInfo> GetPacketFeedbackVector(
       const rtcp::TransportFeedback& feedback);
@@ -61,6 +67,7 @@ class TransportFeedbackAdapter : public TransportFeedbackObserver,
   const bool send_side_bwe_with_overhead_;
   rtc::CriticalSection lock_;
   rtc::CriticalSection bwe_lock_;
+  rtc::CriticalSection observers_lock_;
   int transport_overhead_bytes_per_packet_ GUARDED_BY(&lock_);
   SendTimeHistory send_time_history_ GUARDED_BY(&lock_);
   std::unique_ptr<DelayBasedBwe> delay_based_bwe_ GUARDED_BY(&bwe_lock_);
@@ -69,6 +76,8 @@ class TransportFeedbackAdapter : public TransportFeedbackObserver,
   int64_t last_timestamp_us_;
   BitrateController* const bitrate_controller_;
   std::vector<PacketInfo> last_packet_feedback_vector_;
+  std::vector<TransportFeedbackAdapterObserver*>
+      observers_ GUARDED_BY(&observers_lock_);
 };
 
 }  // namespace webrtc