Fixes for cr-settings-date-time-page

chrome/browser/resources/settings/date_time_page/date_time_page.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
  * 'cr-settings-date-time-page' is the settings page containing date-time
  * settings.
  *
  * Example:
@@ skipping 26 matching lines @@
     route: {
       type: String,
       value: ''
     },
 
     /**
      * Whether the page is a subpage.
      */
     subpage: {
       type: Boolean,
-      value: false
-    }
+      value: false,
+      readOnly: true
+    },
 
     /**
      * ID of the page.
      */
     PAGE_ID: {
       type: String,
-      value: 'date-time'
+      value: 'date-time',
+      readOnly: true
     },
 
     /**
      * Title for the page header and navigation menu.
      */
     pageTitle: {
       type: String,
       value: function() { return loadTimeData.getString('dateTimePageTitle'); }
     },
 
     /**
      * Name of the 'core-icon' to show.
      */
     icon: {
       type: String,
-      value: 'device:access-time'
+      value: 'device:access-time',
+      readOnly: true
     },
   },
 });