Remove unused member variables. No functional change.

net/quic/congestion_control/tcp_cubic_sender.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.
 //
 // TCP cubic send side congestion algorithm, emulates the behavior of TCP cubic.
 
 #ifndef NET_QUIC_CONGESTION_CONTROL_TCP_CUBIC_SENDER_H_
 #define NET_QUIC_CONGESTION_CONTROL_TCP_CUBIC_SENDER_H_
 
 #include "base/basictypes.h"
@@ skipping 112 matching lines @@
   // Slow start congestion window in packets, aka ssthresh.
   QuicPacketCount slowstart_threshold_;
 
   // Whether the last loss event caused us to exit slowstart.
   // Used for stats collection of slowstart_packets_lost
   bool last_cutback_exited_slowstart_;
 
   // Maximum number of outstanding packets for tcp.
   QuicPacketCount max_tcp_congestion_window_;
 
-  const QuicClock* clock_;
-
   DISALLOW_COPY_AND_ASSIGN(TcpCubicSender);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CONGESTION_CONTROL_TCP_CUBIC_SENDER_H_