Implement ChromeVox next/previous line, link, and heading.

chrome/browser/resources/chromeos/chromevox/testing/common.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.
+
+// Common testing utilities.
+
+/**
+ * Shortcut for document.getElementById.
+ * @param {string} id of the element.
+ * @return {HTMLElement} with the id.
+ */
+function $(id) {
+  return document.getElementById(id);
+}
+
+/**
+ * @constructor
+ */
+var TestUtils = function() {};
+
+/**
+ * Extracts some inlined html encoded as a comment inside a function,
+ * so you can use it like this:
+ *
+ * this.appendDoc(function() {/*!
+ *     <p>Html goes here</p>
+ * * /});
+ *
+ * @param {Function} commentEncodedHtml The html , embedded as a
+ *     comment inside an anonymous function - see example, above.
+ * @return {string} The html text.
+*/
+TestUtils.extractHtmlFromCommentEncodedString = function(commentEncodedHtml) {
+  return commentEncodedHtml.toString().
+      replace(/^[^\/]+\/\*!?/, '').
+      replace(/\*\/[^\/]+$/, '');
+};