Fix header guards in //net.

net/dns/address_sorter_posix.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/dns/address_sorter_posix.h"
 
 #include <netinet/in.h>
 
 #include <memory>
 #include <utility>
@@ skipping 379 matching lines @@
   info->label = GetPolicyValue(label_table_, address);
 }
 
 // static
 std::unique_ptr<AddressSorter> AddressSorter::CreateAddressSorter() {
   return std::unique_ptr<AddressSorter>(
       new AddressSorterPosix(ClientSocketFactory::GetDefaultFactory()));
 }
 
 }  // namespace net
-