Add a chrome://nacl page to show if NaCl is enabled and if PNaCl is installed.

chrome/browser/resources/about_nacl.js

+// 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.
+
+var nacl = nacl || {};
+
+(function() {
+  /**
+   * Takes the |moduleListData| input argument which represents data about
+   * the currently available modules and populates the html jstemplate
+   * with that data. It expects an object structure like the above.
+   * @param {Object} moduleListData Information about available modules
+   */
+  function renderTemplate(moduleListData) {
+    // Process the template.
+    var input = new JsEvalContext(moduleListData);
+    var output = $('naclInfoTemplate');
+    jstProcess(input, output);
+  };
+
+  /**
+   * Asks the C++ NaClUIDOMHandler to get details about the NaCl and return
+   * the data in returnNaClInfo() (below).
+   */
+  function requestNaClInfo() {
+    chrome.send('requestNaClInfo');
+  };
+
+  /**
+   * Called by the WebUI to re-populate the page with data representing the
+   * current state of NaCl.
+   * @param {Object} moduleListData Information about available modules
+   */
+  nacl.returnNaClInfo = function(moduleListData) {
+    $('loading-message').hidden = 'hidden';
+    $('body-container').hidden = '';
+    renderTemplate(moduleListData);
+  };
+
+  // Get data and have it displayed upon loading.
+  document.addEventListener('DOMContentLoaded', requestNaClInfo);
+})();