Include unistd.h in quic_socket_utils.cc

net/tools/quic/platform/impl/quic_socket_utils.cc

 // 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.
 
 #include "net/tools/quic/platform/impl/quic_socket_utils.h"
 
 #include <errno.h>
 #include <linux/net_tstamp.h>
 #include <netinet/in.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/uio.h>
+#include <unistd.h>
 #include <string>
 
 #include "net/quic/core/quic_packets.h"
 #include "net/quic/platform/api/quic_bug_tracker.h"
 #include "net/quic/platform/api/quic_flags.h"
 #include "net/quic/platform/api/quic_logging.h"
 #include "net/quic/platform/api/quic_socket_address.h"
 
 #ifndef SO_RXQ_OVFL
 #define SO_RXQ_OVFL 40
@@ skipping 284 matching lines @@
   rc = SetGetSoftwareReceiveTimestamp(fd);
   if (rc < 0) {
     QUIC_LOG(WARNING) << "SO_TIMESTAMPING not supported; using fallback: "
                       << strerror(errno);
   }
 
   return fd;
 }
 
 }  // namespace net