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..27a7de87583c27412a7379510cb3a374b91b3fa4 100644
--- a/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
+++ b/webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h
@@ -337,13 +337,15 @@ struct PacketFeedback {
   PacedPacketInfo pacing_info;
 };
 
+// TODO(elad.alon): See TODO attached to TransportFeedbackAdapterObserver.
 class TransportFeedbackObserver {
  public:
   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 +354,30 @@ class TransportFeedbackObserver {
   virtual std::vector<PacketFeedback> GetTransportFeedbackVector() const = 0;
 };
 
+// TODO(elad.alon): After the current TransportFeedbackObserver becomes obsolete
+// and is removed, reuse the name "TransportFeedbackObserver" for the class
+// currently named "TransportFeedbackAdapterObserver".
+// Background: The only implementers of this interface are
+// CongestionController and TransportFeedbackProxy.
+// CongestionController uses it to expose only a small subset of its
+// capabilities.
+// TransportFeedbackProxy is a temporary solution which exists to allow passing
+// the CongestionController down at a later stage.
+// Ideally, we'd get rid of this altogether, exposing CC. This will be done
+// after the order-of-creation issues have been resolved, and
+// TransportFeedbackProxy therefore removed. Then, we'll remove

[minyue-webrtc, 2017/03/22 07:51:39]

I still think the last sentence 

"Then, we'll remove TransportFeedbackAdapterObserver, reuse the name
TransportFeedbackObserver for TransportFeedbackAdapterObserver, and only have
one observer."

is confusing.

The first sentence said "TransportFeedbackObserver will be removed" but now it
becomes "TransportFeedbackAdapterObserver", I think it is a typo.

[elad.alon_webrtc.org, 2017/03/22 09:36:31]

Done.

+// TransportFeedbackAdapterObserver, reuse the name
+// TransportFeedbackObserver for TransportFeedbackAdapterObserver, and only
+// have one observer.
+class TransportFeedbackAdapterObserver {
+ public:
+  virtual ~TransportFeedbackAdapterObserver() = default;
+
+  virtual void OnPacketAdded(uint32_t ssrc, uint16_t seq_num) = 0;
+  virtual void OnNewTransportFeedbackVector(
+      const std::vector<PacketFeedback>& packet_feedback_vector) = 0;
+};
+
 class RtcpRttStats {
  public:
   virtual void OnRttUpdate(int64_t rtt) = 0;