Correctly handle NACK-based "retransmission" of packets which no longer

net/quic/quic_sent_packet_manager.h

 // Copyright 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.
 
 #ifndef NET_QUIC_QUIC_SENT_PACKET_MANAGER_H_
 #define NET_QUIC_QUIC_SENT_PACKET_MANAGER_H_
 
 #include <deque>
 #include <list>
 #include <map>
@@ skipping 277 matching lines @@
   // the packet |sequence_number|.
   QuicSequenceNumberLength GetSequenceNumberLength(
       QuicPacketSequenceNumber sequence_number) const;
 
   // Clears up to |num_to_clear| previous transmissions in order to make room
   // in the ack frame for new acks.
   void ClearPreviousRetransmissions(size_t num_to_clear);
 
   void CleanupPacketHistory();
 
+  // Removes |sequence_number| as a previous transmission of any other packets.
+  void RemovePreviousTransmission(QuicPacketSequenceNumber sequence_number);
+
   // Newly serialized retransmittable and fec packets are added to this map,
   // which contains owning pointers to any contained frames.  If a packet is
   // retransmitted, this map will contain entries for both the old and the new
   // packet. The old packet's retransmittable frames entry will be NULL, while
   // the new packet's entry will contain the frames to retransmit.
   // If the old packet is acked before the new packet, then the old entry will
   // be removed from the map and the new entry's retransmittable frames will be
   // set to NULL.
   UnackedPacketMap unacked_packets_;
 
@@ skipping 29 matching lines @@
   // Maximum number of tail loss probes to send before firing an RTO.
   size_t max_tail_loss_probes_;
   bool using_pacing_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicSentPacketManager);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_SENT_PACKET_MANAGER_H_