Attach TransportFeedbackPacketLossTracker to ANA (PLR only)

webrtc/modules/congestion_controller/transport_feedback_adapter.cc

Index: webrtc/modules/congestion_controller/transport_feedback_adapter.cc
diff --git a/webrtc/modules/congestion_controller/transport_feedback_adapter.cc b/webrtc/modules/congestion_controller/transport_feedback_adapter.cc
index 7780024a8684ab200860ae21c8791611a9239b35..0ca48ae5a266e1b83d74fe7d674e6ebb8525e5cd 100644
--- a/webrtc/modules/congestion_controller/transport_feedback_adapter.cc
+++ b/webrtc/modules/congestion_controller/transport_feedback_adapter.cc
@@ -34,16 +34,52 @@ TransportFeedbackAdapter::TransportFeedbackAdapter(const Clock* clock)
       current_offset_ms_(kNoTimestamp),
       last_timestamp_us_(kNoTimestamp) {}
 
-TransportFeedbackAdapter::~TransportFeedbackAdapter() {}
+TransportFeedbackAdapter::~TransportFeedbackAdapter() {
+  RTC_DCHECK(observers_.empty());
+}
+
+void TransportFeedbackAdapter::RegisterTransportFeedbackAdapterObserver(
+    TransportFeedbackAdapterObserver* observer) {
+  rtc::CritScope cs(&observers_lock_);
+  RTC_DCHECK(observer);
+  if (std::find(observers_.begin(), observers_.end(), observer) ==
+      observers_.end()) {
+    observers_.push_back(observer);
+  } else {
+    RTC_NOTREACHED();
+  }
+}
 
-void TransportFeedbackAdapter::AddPacket(uint16_t sequence_number,
+void TransportFeedbackAdapter::DeRegisterTransportFeedbackAdapterObserver(
+    TransportFeedbackAdapterObserver* observer) {
+  rtc::CritScope cs(&observers_lock_);
+  RTC_DCHECK(observer);
+  auto elem = std::find(observers_.begin(), observers_.end(), observer);
+  if (elem != observers_.end()) {
+    observers_.erase(elem);
+  } else {
+    RTC_NOTREACHED();
+  }
+}
+
+void TransportFeedbackAdapter::AddPacket(uint32_t ssrc,
+                                         uint16_t sequence_number,
                                          size_t length,
                                          const PacedPacketInfo& pacing_info) {
-  rtc::CritScope cs(&lock_);
-  if (send_side_bwe_with_overhead_) {
-    length += transport_overhead_bytes_per_packet_;
+  {
+    rtc::CritScope cs(&lock_);
+    if (send_side_bwe_with_overhead_) {
+      length += transport_overhead_bytes_per_packet_;
+    }
+    send_time_history_.AddAndRemoveOld(sequence_number, length, pacing_info);
+  }
+
+  {
+    rtc::CritScope cs(&observers_lock_);
+    for (auto observer : observers_) {
+      observer->OnPacketAdded(ssrc, sequence_number);
+    }
   }
-  send_time_history_.AddAndRemoveOld(sequence_number, length, pacing_info);
 }
 
 void TransportFeedbackAdapter::OnSentPacket(uint16_t sequence_number,
@@ -141,6 +177,12 @@ std::vector<PacketFeedback> TransportFeedbackAdapter::GetPacketFeedbackVector(
 void TransportFeedbackAdapter::OnTransportFeedback(
     const rtcp::TransportFeedback& feedback) {
   last_packet_feedback_vector_ = GetPacketFeedbackVector(feedback);
+  {
+    rtc::CritScope cs(&observers_lock_);
+    for (auto observer : observers_) {
+      observer->OnTransportFeedback(feedback);
+    }
+  }
 }
 
 std::vector<PacketFeedback>