Attach TransportFeedbackPacketLossTracker to ANA (PLR only)

webrtc/voice_engine/channel.h

Index: webrtc/voice_engine/channel.h
diff --git a/webrtc/voice_engine/channel.h b/webrtc/voice_engine/channel.h
index 60e6f6040cd906f15c7a2b831db58d8b6be30580..09e3ed327e0b9a0ba2b9e531f619a6df82e60992 100644
--- a/webrtc/voice_engine/channel.h
+++ b/webrtc/voice_engine/channel.h
@@ -33,6 +33,7 @@
 #include "webrtc/voice_engine/include/voe_base.h"
 #include "webrtc/voice_engine/include/voe_network.h"
 #include "webrtc/voice_engine/shared_data.h"
+#include "webrtc/voice_engine/transport_feedback_packet_loss_tracker.h"
 #include "webrtc/voice_engine/voice_engine_defines.h"
 
 namespace rtc {
@@ -376,8 +377,15 @@ class Channel
   // From OverheadObserver in the RTP/RTCP module
   void OnOverheadChanged(size_t overhead_bytes_per_packet) override;
 
+  // Note: The existence of this function alongside OnUplinkPacketLossRate is
+  // a compromise. We want the encoder to be agnostic of the PLR source, but
+  // we also don't want it to receive conflicting information from TWCC and
+  // from RTCP-XR.
+  void OnTwccBasedUplinkPacketLossRate(
+      const rtc::Optional<float>& packet_loss_rate);

[minyue-webrtc, 2017/03/17 09:20:32]

I think the arg should be "float packet_loss_rate", if there is no
packet_loss_rate, why should we call this function?

[elad.alon_webrtc.org, 2017/03/17 10:10:33]

An unknown is possible when a new feedback arrives after a long period of
inactivity, making the window go back down below the thresholds for determining
"statistically significant" (kind of) values. In such a case, ANA should decide
what to do, not the tracker (not passing new input = pushing to keep the last
decision).

+
  protected:
-  void OnIncomingFractionLoss(int fraction_lost);
+  void OnUplinkPacketLossRate(float packet_loss_rate);
 
  private:
   bool InputMute() const;
@@ -504,6 +512,8 @@ class Channel
 
   // TODO(ossu): Remove once GetAudioDecoderFactory() is no longer needed.
   rtc::scoped_refptr<AudioDecoderFactory> decoder_factory_;
+
+  const bool use_twcc_plr_for_ana_;
 };
 
 }  // namespace voe