MD Settings: Third party VPN support

ui/webui/resources/js/i18n_behavior.js

 // Copyright 2015 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.
 
 /**
  * @fileoverview
  * 'I18nBehavior' is a behavior to mix in loading of
  * internationalization strings.
  *
  * Example:
@@ skipping 49 matching lines @@
 
   /**
    * Returns true if a translation exists for |id|.
    * @param {string} id
    * @return {boolean}
    */
   i18nExists: function(id) {
     return loadTimeData.valueExists(id);
   },
 };
+
+/**
+ * TODO(stevenjb): Replace with an interface. b/24294625
+ * @typedef {{
+ *   i18n: function(string, ...string): string}},
+ *   i18nAdvanced: function({
+ *     substitutions: (Array<string>|undefined),
+ *     attrs: (Object<function(Node, string):boolean>|undefined),
+ *     tags: (Array<string>|undefined)}, opts),
+ *   i18nExists: function(string)
+ * }}
+ */
+I18nBehavior.Proto;