Use JSON schema compiler for i18n api

chrome/common/extensions/api/i18n.json

 // 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.
 
 [
   {
     "namespace": "i18n",
     "types": [],
     "functions": [
       {
         "name": "getAcceptLanguages",
         "type": "function",
         "description": "Gets the accept-languages of the browser. This is different from the locale used by the browser; to get the locale, use <code>window.navigator.language</code>.",
         "parameters": [
           {
             "type": "function",
             "name": "callback",
             "parameters": [
               {"name": "languages", "type": "array", "items": {"type": "string"}, "description": "Array of the accept languages of the browser, such as en-US,en,zh-CN"}
             ]
           }
         ]
       },
       {
         "name": "getMessage",
         "type": "function",
         "unprivileged": true,
         "description": "Gets the localized string for the specified message. If the message is missing, this method returns an empty string (''). If the format of the <code>getMessage()</code> call is wrong &mdash; for example, <em>messageName</em> is not a string or the <em>substitutions</em> array has more than 9 elements &mdash; this method returns <code>undefined</code>.",
         "parameters": [
-          { "type": "string",
+          {
+            "type": "string",
             "name": "messageName",
             "description": "The name of the message, as specified in the <a href='i18n-messages.html'><code>messages.json</code></a> file."
           },
           {
             "type": "any",
             "name": "substitutions",
             "optional": true,
             "description": "Up to 9 substitution strings, if the message requires any."
           }
         ],
         "returns": {
           "type": "string",
           "description": "Message localized for current locale."
         }
       }
     ],
     "events": []
   }
 ]