Fix net_export.h includes.

net/tools/quic/synchronous_host_resolver.h

 // Copyright (c) 2015 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.
 //
 // A simple class for resolving hostname synchronously.
 
 #ifndef NET_TOOLS_QUIC_SYNCHRONOUS_HOST_RESOLVER_H_
 #define NET_TOOLS_QUIC_SYNCHRONOUS_HOST_RESOLVER_H_
 
 #include "net/base/address_list.h"
-#include "net/base/net_export.h"
 #include "net/dns/host_resolver.h"
 
 namespace net {
 
 
 class SynchronousHostResolver {
  public:
   static int Resolve(const std::string& host, AddressList* addresses);
 };
 
 }  // namespace net
 
 #endif  // NET_TOOLS_QUIC_SYNCHRONOUS_HOST_RESOLVER_H_