WebUI: add functional test for text_defaults.css

chrome/test/data/webui/text_defaults_browsertest.js

+// Copyright 2016 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.
+
+/**
+ * Test fixture for testing async methods of cr.js.
+ * @constructor
+ * @extends testing.Test
+ */
+function TextDefaultsTest() {}
+
+TextDefaultsTest.prototype = {
+  __proto__: testing.Test.prototype,
+
+  /**
+   * Must be on same domain as text_defaults.css (chrome://resources).
+   * @override
+   */
+  browsePreload: 'chrome://resources/html/assert.html',
+
+  /** @override */
+  isAsync: true,
+};
+
+/**
+ * @param {string} html Text, possibly with HTML &entities; in it.
+ * @return {string} The HTML decoded text.
+ */
+function decodeHtmlEntities(html) {
+  var element = document.createElement('div');
+  element.innerHTML = html;
+  return element.textContent;
+}
+
+TEST_F('TextDefaultsTest', 'ScrapeStyles', function() {
+  var link = document.createElement('link');
+  link.rel = 'stylesheet';
+  link.href = 'chrome://resources/css/text_defaults.css';
+  link.onload = function() {
+    var fontFamily = link.sheet.rules[1].style['font-family'];
+    assertNotEquals('', fontFamily);
+    assertEquals(decodeHtmlEntities(fontFamily), fontFamily);
+    testDone();
+  };
+  document.body.appendChild(link);
+});
+
+TEST_F('TextDefaultsTest', 'ScrapeMDStyles', function() {
+  var link = document.createElement('link');
+  link.rel = 'stylesheet';
+  link.href = 'chrome://resources/css/text_defaults_md.css';
+  link.onload = function() {
+    var fontFamily = link.sheet.rules[2].style['font-family'];
+    assertNotEquals('', fontFamily);
+    assertEquals(decodeHtmlEntities(fontFamily), fontFamily);
+    testDone();
+  };
+  document.body.appendChild(link);
+});