HostResolver is exposed to plugin.

ppapi/ppapi_shared.gypi

 # 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.
 
 {
    'variables': {
      'conditions': [
         ['inside_chromium_build==0', {
             'webkit_src_dir': '../../../..',
         },{
@@ skipping 115 matching lines @@
         'shared_impl/var_tracker.cc',
         'shared_impl/var_tracker.h',
         # TODO(viettrungluu): Split these out; it won't be used in NaCl.
         'shared_impl/private/net_address_private_impl.cc',
         'shared_impl/private/net_address_private_impl.h',
 
         'shared_impl/private/ppb_browser_font_trusted_shared.cc',
         'shared_impl/private/ppb_browser_font_trusted_shared.h',
         'shared_impl/private/ppb_char_set_shared.cc',
         'shared_impl/private/ppb_char_set_shared.h',
+
+        'shared_impl/private/ppb_host_resolver_shared.cc',
+        'shared_impl/private/ppb_host_resolver_shared.h',
         'shared_impl/private/ppb_tcp_server_socket_shared.cc',
         'shared_impl/private/ppb_tcp_server_socket_shared.h',
         'shared_impl/private/tcp_socket_private_impl.cc',
         'shared_impl/private/tcp_socket_private_impl.h',
         'shared_impl/private/udp_socket_private_impl.cc',
         'shared_impl/private/udp_socket_private_impl.h',
 
         'thunk/enter.cc',
         'thunk/enter.h',
         'thunk/ppb_audio_api.h',
@@ skipping 42 matching lines @@
         'thunk/ppb_flash_net_connector_api.h',
         'thunk/ppb_flash_net_connector_thunk.cc',
         'thunk/ppb_fullscreen_thunk.cc',
         'thunk/ppb_gamepad_thunk.cc',
         'thunk/ppb_gles_chromium_texture_mapping_thunk.cc',
         'thunk/ppb_graphics_2d_api.h',
         'thunk/ppb_graphics_2d_thunk.cc',
         'thunk/ppb_graphics_3d_api.h',
         'thunk/ppb_graphics_3d_thunk.cc',
         'thunk/ppb_graphics_3d_trusted_thunk.cc',
+        'thunk/ppb_host_resolver_private_api.h',
+        'thunk/ppb_host_resolver_private_thunk.cc',
         'thunk/ppb_image_data_api.h',
         'thunk/ppb_image_data_thunk.cc',
         'thunk/ppb_image_data_trusted_thunk.cc',
         'thunk/ppb_instance_api.h',
         'thunk/ppb_instance_thunk.cc',
         'thunk/ppb_layer_compositor_api.h',
         'thunk/ppb_layer_compositor_thunk.cc',
         'thunk/ppb_message_loop_api.h',
         'thunk/ppb_messaging_thunk.cc',
         'thunk/ppb_mouse_lock_thunk.cc',
@@ skipping 34 matching lines @@
         'thunk/ppb_websocket_api.h',
         'thunk/ppb_websocket_thunk.cc',
         'thunk/ppb_widget_api.h',
         'thunk/ppb_widget_thunk.cc',
         'thunk/ppb_zoom_thunk.cc',
         'thunk/thunk.h',
       ],
     },
   ],
 }