Add GetDebugState() in SendAlgorithmInterface().

net/quic/core/congestion_control/pacing_sender.h

 // Copyright (c) 2013 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.
 //
 // A send algorithm that adds pacing on top of an another send algorithm.
 // It uses the underlying sender's pacing rate to schedule packets.
 // It also takes into consideration the expected granularity of the underlying
 // alarm to ensure that alarms are not set too aggressively, and err towards
 // sending packets too early instead of too late.
 
@@ skipping 45 matching lines @@
   QuicTime::Delta TimeUntilSend(QuicTime now,
                                 QuicByteCount bytes_in_flight) const override;
   QuicBandwidth PacingRate(QuicByteCount bytes_in_flight) const override;
   QuicBandwidth BandwidthEstimate() const override;
   QuicTime::Delta RetransmissionDelay() const override;
   QuicByteCount GetCongestionWindow() const override;
   bool InSlowStart() const override;
   bool InRecovery() const override;
   QuicByteCount GetSlowStartThreshold() const override;
   CongestionControlType GetCongestionControlType() const override;
+  std::string GetDebugState() const override;
   // End implementation of SendAlgorithmInterface.
 
  private:
   // Underlying sender. Owned if |owns_sender_| is true.
   SendAlgorithmInterface* sender_;
   // If not QuicBandidth::Zero, the maximum rate the PacingSender will use.
   QuicBandwidth max_pacing_rate_;
 
   // Number of unpaced packets to be sent before packets are delayed.
   uint32_t burst_tokens_;
   // Send time of the last packet considered delayed.
   QuicTime last_delayed_packet_sent_time_;
   QuicTime ideal_next_packet_send_time_;  // When can the next packet be sent.
   mutable bool was_last_send_delayed_;  // True when the last send was delayed.
   bool owns_sender_;                    // True if PacingSender owns |sender_|.
 
   DISALLOW_COPY_AND_ASSIGN(PacingSender);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CONGESTION_CONTROL_PACING_SENDER_H_