Use setProperties for IP Config.

chrome/browser/resources/options/chromeos/onc_data.js

 // Copyright 2014 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 ONC Data support class. Wraps a dictionary object containing
  * ONC managed or unmanaged dictionaries. Supports nested dictionaries,
  * e.g. data.getManagedProperty('VPN.Type').
  */
 
@@ skipping 122 matching lines @@
         return undefined;
       if (property['UserEditable'])
         return property['UserPolicy'];
       if (property['DeviceEditable'])
         return property['DevicePolicy'];
       // No value recommended by policy.
       return undefined;
     },
 
     /**
+     * Returns true if the ONC property exists, false otherwise.
+     * @param {string} key The property key.
+     * @return {bool} Whether the property exists.
+     */
+    hasValue: function(key) {
+      var property = this.getManagedProperty(key);
+      return property != undefined;
+    },
+
+    /**
      * Returns the Source of this configuration. If undefined returns 'None'.
      * @return {string} The configuration source: 'None', 'User', 'Device',
      *                  'UserPolicy', or 'DevicePolicy'.
      */
     getSource: function() {
       var source = this.getActiveValue('Source');
       if (source == undefined)
         return 'None';
       assert(typeof source == 'string');
       return source;
@@ skipping 31 matching lines @@
      */
     getData: function() {
       return this.data_;
     }
   };
 
   return {
     OncData: OncData
   };
 });