HostResolver is exposed to Native Client.

ppapi/native_client/src/shared/ppapi_proxy/ppapi_proxy_untrusted.gyp

 # 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.
 
 {
   'includes': [
     '../../../../../native_client/build/common.gypi',
   ],
   'targets': [
     {
@@ skipping 47 matching lines @@
           'plugin_ppb_cursor_control.cc',
           'plugin_ppb_file_io.cc',
           'plugin_ppb_file_system.cc',
           'plugin_ppb_file_ref.cc',
           'plugin_ppb_find.cc',
           'plugin_ppb_font.cc',
           'plugin_ppb_fullscreen.cc',
           'plugin_ppb_gamepad.cc',
           'plugin_ppb_graphics_2d.cc',
           'plugin_ppb_graphics_3d.cc',
+          'plugin_ppb_host_resolver_private.cc',
           'plugin_ppb_image_data.cc',
           'plugin_ppb_input_event.cc',
           'plugin_ppb_instance.cc',
           'plugin_ppb_memory.cc',
           'plugin_ppb_messaging.cc',
           'plugin_ppb_mouse_lock.cc',
           'plugin_ppb_net_address_private.cc',
           'plugin_ppb_pdf.cc',
           'plugin_ppb_scrollbar.cc',
           'plugin_ppb_tcp_server_socket_private.cc',
@@ skipping 30 matching lines @@
           'view_data.cc',
           # Autogenerated files
           'ppp_rpc_server.cc',
           'ppb_rpc_client.cc',
           'upcall_client.cc'
         ],
       },
     },
   ],
 }