Remove an impossible check in QuicConnection for when a packet is

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 112 matching lines @@
   // Returns the smallest sequence number of a sent packet which has not been
   // acked by the peer.  Excludes any packets which have been retransmitted
   // with a new sequence number. If all packets have been acked, returns the
   // sequence number of the next packet that will be sent.
   QuicPacketSequenceNumber GetLeastUnackedSentPacket() const;
 
   // Returns the set of sequence numbers of all unacked packets.
   // Test only.
   SequenceNumberSet GetUnackedPackets() const;
 
-  // Returns true if |sequence_number| is a previous transmission of packet.
-  bool IsPreviousTransmission(QuicPacketSequenceNumber sequence_number) const;
-
   // Called when a congestion feedback frame is received from peer.
   virtual void OnIncomingQuicCongestionFeedbackFrame(
       const QuicCongestionFeedbackFrame& frame,
       const QuicTime& feedback_receive_time);
 
   // Called when we have sent bytes to the peer.  This informs the manager both
   // the number of bytes sent and if they were retransmitted.  Returns true if
   // the sender should reset the retransmission timer.
   virtual bool OnPacketSent(QuicPacketSequenceNumber sequence_number,
                             QuicTime sent_time,
@@ skipping 194 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_