Add ARC version to help and version pages

components/version_ui/resources/about_version.js

 // Copyright (c) 2011 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.
 
 /**
  * Callback from the backend with the list of variations to display.
  * This call will build the variations section of the version page, or hide that
  * section if there are none to display.
  * @param {!Array<string>} variationsList The list of variations.
  */
@@ skipping 22 matching lines @@
 }
 
 /**
  * Callback from the backend with the OS version to display.
  * @param {string} osVersion The OS version to display.
  */
 function returnOsVersion(osVersion) {
   $('os_version').textContent = osVersion;
 }
 
+
+/**
+ * Callback from the backend with the ARC version to display.
+ * @param {string} arcVersion The ARC version to display.
+ */
+function returnARCVersion(arcVersion) {
+  $('arc_version').textContent = arcVersion;
+  $('arc_holder').hidden = !arcVersion;
+}
+
 /* All the work we do onload. */
 function onLoadWork() {
   chrome.send('requestVersionInfo');
+  $('arc_holder').hidden = true;
 }
 
 document.addEventListener('DOMContentLoaded', onLoadWork);