Add GetDebugState() in SendAlgorithmInterface().

net/quic/core/quic_multipath_sent_packet_manager.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.
 
 #ifndef NET_QUIC_QUIC_MULTIPATH_SENT_PACKET_MANAGER_H_
 #define NET_QUIC_QUIC_MULTIPATH_SENT_PACKET_MANAGER_H_
 
 #include <vector>
 
 #include "net/base/net_export.h"
@@ skipping 114 matching lines @@
       QuicByteCount max_packet_length) const override;
 
   // Returns the size of the current congestion window size on the default path
   // in bytes.
   QuicByteCount GetCongestionWindowInBytes() const override;
 
   // Returns the size of the slow start congestion window in number of 1460 byte
   // TCP segments on the default path.
   QuicPacketCount GetSlowStartThresholdInTcpMss() const override;
 
+  // Returns debugging information about the state of the congestion
+  // controller for all paths.
+  std::string GetDebugState() const override;
+
   // No longer retransmit data for |stream_id| on all paths and any pending
   // retransmissions in pending_retransmissions_.
   void CancelRetransmissionsForStream(QuicStreamId stream_id) override;
 
   void OnConnectionMigration(QuicPathId path_id,
                              PeerAddressChangeType type) override;
 
   bool IsHandshakeConfirmed() const override;
 
   // Sets debug delegate for all active paths.
@@ skipping 62 matching lines @@
 
   // Does not own this delegate.
   QuicConnectionCloseDelegateInterface* delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicMultipathSentPacketManager);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_MULTIPATH_SENT_PACKET_MANAGER_H_