switch mediaGalleries to .idl api definition

chrome/common/extensions/api/api.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.
 
 {
   'targets': [
     {
       'target_name': 'api',
       'type': 'static_library',
       'sources': [
@@ skipping 20 matching lines @@
           'windows.json',
         ],
         'idl_schema_files': [
           'alarms.idl',
           'app_window.idl',
           'downloads.idl',
           'experimental_bluetooth.idl',
           'experimental_discovery.idl',
           'experimental_dns.idl',
           'experimental_idltest.idl',
+          'experimental_media_galleries.idl',
           'experimental_serial.idl',
           'experimental_socket.idl',
           'experimental_usb.idl',
           'file_system.idl',
         ],
         'cc_dir': 'chrome/common/extensions/api',
         'root_namespace': 'extensions::api',
       },
       'conditions': [
         ['OS=="android"', {
           'idl_schema_files!': [
             'experimental_usb.idl',
           ],
         }],
         ['OS!="chromeos"', {
           'json_schema_files!': [
             'file_browser_handler_internal.json',
           ],
         }],
       ],
     },
   ],
 }