Add IDL capability to json_schema_compiler.

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': [
         '<@(json_schema_files)',
+        '<@(idl_schema_files)',
       ],
       'includes': ['../../../../build/json_schema_compile.gypi'],
       'variables': {
         'chromium_code': 1,
         'json_schema_files': [
           'experimental.declarative.json',
           'permissions.json',
           'tabs.json',
           'windows.json',
         ],
+        'idl_schema_files': [
+          'experimental.dns.idl',
+        ],
         'cc_dir': 'chrome/common/extensions/api',
         'root_namespace': 'extensions::api',
       },
     },
   ],
 }