Port aria_util_test.js to run as a WebUI test.

chrome/browser/resources/chromeos/chromevox/testing/chromevox_unittest_base.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.
+
+/**
+ * Shortcut for document.getElementById.
+ * @param {string} id of the element.
+ * @return {HTMLElement} with the id.
+ */
+function $(id) {
+  return document.getElementById(id);
+}
+
+/**
+ * Base test fixture for ChromeVox unit tests.
+ *
+ * Note that while conceptually these are unit tests, these tests need
+ * to run in a full web page, so they're actually run as WebUI browser
+ * tests.
+ *
+ * @constructor
+ * @extends {testing.Test}
+ */
+function ChromeVoxUnitTestBase() {}
+
+ChromeVoxUnitTestBase.prototype = {
+  __proto__: testing.Test.prototype,
+
+  /** @override */
+  browsePreload: DUMMY_URL,
+
+  /**
+   * Loads some inlined html into the current document, replacing
+   * whatever was there previously. To use it, call it with the html
+   * inside an inline comment, like this:
+   *
+   * this.loadDoc(function() {/*!
+   *     <p>Html goes here</p>
+   * * /});
+   */
+  loadDoc: function(commentEncodedHtml) {
+    var html = commentEncodedHtml.toString().
+        replace(/^[^\/]+\/\*!?/, '').
+        replace(/\*\/[^\/]+$/, '');
+    document.open();
+    document.write(html);
+    document.close();
+  }
+};