Update from chromium https://crrev.com/302282

net/quic/congestion_control/send_algorithm_interface.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // The pure virtual class for send side congestion control algorithm.
 
 #ifndef NET_QUIC_CONGESTION_CONTROL_SEND_ALGORITHM_INTERFACE_H_
 #define NET_QUIC_CONGESTION_CONTROL_SEND_ALGORITHM_INTERFACE_H_
 
 #include <algorithm>
@@ skipping 24 matching lines @@
                                         QuicConnectionStats* stats);
 
   virtual ~SendAlgorithmInterface() {}
 
   virtual void SetFromConfig(const QuicConfig& config, bool is_server) = 0;
 
   // Sets the number of connections to emulate when doing congestion control,
   // particularly for congestion avoidance.  Can be set any time.
   virtual void SetNumEmulatedConnections(int num_connections) = 0;
 
-  // Called when we receive congestion feedback from remote peer.
-  virtual void OnIncomingQuicCongestionFeedbackFrame(
-      const QuicCongestionFeedbackFrame& feedback,
-      QuicTime feedback_receive_time) = 0;
-
   // Indicates an update to the congestion state, caused either by an incoming
   // ack or loss event timeout.  |rtt_updated| indicates whether a new
   // latest_rtt sample has been taken, |byte_in_flight| the bytes in flight
   // prior to the congestion event.  |acked_packets| and |lost_packets| are
   // any packets considered acked or lost as a result of the congestion event.
   virtual void OnCongestionEvent(bool rtt_updated,
                                  QuicByteCount bytes_in_flight,
                                  const CongestionVector& acked_packets,
                                  const CongestionVector& lost_packets) = 0;
 
@@ skipping 15 matching lines @@
 
   // Called when the last retransmission timeout was spurious.
   virtual void RevertRetransmissionTimeout() = 0;
 
   // Calculate the time until we can send the next packet.
   virtual QuicTime::Delta TimeUntilSend(
       QuicTime now,
       QuicByteCount bytes_in_flight,
       HasRetransmittableData has_retransmittable_data) const = 0;
 
+  // The pacing rate of the send algorithm.  May be zero if the rate is unknown.
   virtual QuicBandwidth PacingRate() const = 0;
 
   // What's the current estimated bandwidth in bytes per second.
   // Returns 0 when it does not have an estimate.
   virtual QuicBandwidth BandwidthEstimate() const = 0;
 
   // Returns true if the current bandwidth estimate is reliable.
   virtual bool HasReliableBandwidthEstimate() const = 0;
 
   // Get the send algorithm specific retransmission delay, called RTO in TCP,
@@ skipping 17 matching lines @@
   // aka ssthresh.  Some send algorithms do not define a slow start
   // threshold and will return 0.
   virtual QuicByteCount GetSlowStartThreshold() const = 0;
 
   virtual CongestionControlType GetCongestionControlType() const = 0;
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CONGESTION_CONTROL_SEND_ALGORITHM_INTERFACE_H_