Add GetDebugState() in SendAlgorithmInterface().

net/quic/core/quic_sent_packet_manager_interface.h

 // Copyright 2016 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.
 
 #ifndef NET_QUIC_QUIC_SENT_PACKET_MANAGER_INTERFACE_H_
 #define NET_QUIC_QUIC_SENT_PACKET_MANAGER_INTERFACE_H_
 
 #include "base/macros.h"
 #include "net/quic/core/quic_protocol.h"
 #include "net/quic/core/quic_sustained_bandwidth_recorder.h"
@@ skipping 134 matching lines @@
       QuicByteCount max_packet_length) const = 0;
 
   // Returns the size of the current congestion window size on the default path
   // in bytes.
   virtual QuicByteCount GetCongestionWindowInBytes() const = 0;
 
   // Returns the size of the slow start congestion window in number of 1460 byte
   // TCP segments on the default path.
   virtual QuicPacketCount GetSlowStartThresholdInTcpMss() const = 0;
 
+  // Returns debugging information about the current state of the
+  // congestion controller.
+  virtual std::string GetDebugState() const = 0;
+
   // No longer retransmit data for |stream_id| on all paths.
   virtual void CancelRetransmissionsForStream(QuicStreamId stream_id) = 0;
 
   // Called when peer address changes and the connection migrates on |path_id|.
   // TODO(fayang): Name of this method is confusing in multipath world because
   // this migration is path level. Need to rename this as OnPeerMigration.
   virtual void OnConnectionMigration(QuicPathId path_id,
                                      PeerAddressChangeType type) = 0;
 
   virtual bool IsHandshakeConfirmed() const = 0;
@@ skipping 14 matching lines @@
 
   // These two methods return the consecutive RTO or TLP count of the default
   // path.
   virtual size_t GetConsecutiveRtoCount() const = 0;
   virtual size_t GetConsecutiveTlpCount() const = 0;
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_SENT_PACKET_MANAGER_INTERFACE_H_