Change the null value for packet sequence numbers to

net/quic/quic_protocol.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_PROTOCOL_H_
 #define NET_QUIC_QUIC_PROTOCOL_H_
 
 #include <stddef.h>
 #include <limits>
 #include <list>
@@ skipping 574 matching lines @@
   // Universal header. All QuicPacket headers will have a connection_id and
   // public flags.
   QuicConnectionId connection_id;
   QuicConnectionIdLength connection_id_length;
   bool reset_flag;
   bool version_flag;
   QuicSequenceNumberLength sequence_number_length;
   QuicVersionVector versions;
 };
 
+// An integer which cannot be a packet sequence number.
+const QuicPacketSequenceNumber kInvalidPacketSequenceNumber = 0;
+
 // Header for Data or FEC packets.
 struct NET_EXPORT_PRIVATE QuicPacketHeader {
   QuicPacketHeader();
   explicit QuicPacketHeader(const QuicPacketPublicHeader& header);
 
   NET_EXPORT_PRIVATE friend std::ostream& operator<<(
       std::ostream& os, const QuicPacketHeader& s);
 
   QuicPacketPublicHeader public_header;
   bool fec_flag;
@@ skipping 431 matching lines @@
   bool in_flight;
   // True if the packet can never be acked, so it can be removed.
   bool is_unackable;
   // True if the packet is an FEC packet.
   bool is_fec_packet;
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_PROTOCOL_H_