[NaCl SDK] nacl_io: implement getaddrinfo()

native_client_sdk/src/libraries/nacl_io/host_resolver.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 LIBRARIES_NACL_IO_HOST_RESOLVER_H_
 #define LIBRARIES_NACL_IO_HOST_RESOLVER_H_
 
 #include "nacl_io/ossocket.h"
 #include "nacl_io/pepper_interface.h"
+#include "sdk_util/simple_lock.h"
 
 #ifdef PROVIDES_SOCKET_API
 
 namespace nacl_io {
 
 class HostResolver {
  public:
   HostResolver();
   ~HostResolver();
 
   void Init(PepperInterface* ppapi);
 
+  void freeaddrinfo(struct addrinfo *res);
+  int getaddrinfo(const char *node, const char *service,
+                  const struct addrinfo *hints,
+                  struct addrinfo **res);
   struct hostent* gethostbyname(const char* name);
-
  private:
   void hostent_initialize();
   void hostent_cleanup();
 
   struct hostent hostent_;
   PepperInterface *ppapi_;
+  sdk_util::SimpleLock gethostbyname_lock_;
 };
 
 }  // namespace nacl_io
 
 #endif  // PROVIDES_SOCKET_API
 #endif  // LIBRARIES_NACL_IO_HOST_RESOLVER_H_