Fix net_export.h includes.

net/dns/mdns_client.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_DNS_MDNS_CLIENT_H_
 #define NET_DNS_MDNS_CLIENT_H_
 
 #include <stdint.h>
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "net/base/ip_endpoint.h"
+#include "net/base/net_export.h"
 #include "net/dns/dns_query.h"
 #include "net/dns/dns_response.h"
 #include "net/dns/record_parsed.h"
 
 namespace net {
 
 class DatagramServerSocket;
 class RecordParsed;
 
 // Represents a one-time record lookup. A transaction takes one
@@ skipping 157 matching lines @@
 // Create sockets, binds socket to MDns endpoint, and sets multicast interface
 // and joins multicast group on for |interface_index|.
 // Returns NULL if failed.
 NET_EXPORT std::unique_ptr<DatagramServerSocket> CreateAndBindMDnsSocket(
     AddressFamily address_family,
     uint32_t interface_index);
 
 }  // namespace net
 
 #endif  // NET_DNS_MDNS_CLIENT_H_