MD Settings: Lazy load the contents of the "advanced" settings.

chrome/test/data/webui/settings/settings_subpage_browsertest.js

 // Copyright 2015 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.
 
 /**
  * @fileoverview Suite of tests to ensure that settings subpages exist and
  * load without errors. Also outputs approximate load times for each subpage.
  */
 
 GEN_INCLUDE(['settings_page_browsertest.js']);
 
 /**
  * @constructor
  * @extends {SettingsPageBrowserTest}
- *
- * @param {string} pageId Just 'basic'. TODO(michaelpg): Add 'about' if we want
- *     to, but that requires wrapping its sole <settings-section> in a dom-if.
  */
-function SettingsSubPageBrowserTest(pageId) {
-  /** @type {string} */
-  this.pageId = pageId;
-
+function SettingsSubPageBrowserTest() {
   /** @type {!Array<string>} */
   this.subPages = [];
 }
 
 SettingsSubPageBrowserTest.prototype = {
   __proto__: SettingsPageBrowserTest.prototype,
 
   /** @override */
   preLoad: function() {
     SettingsPageBrowserTest.prototype.preLoad.call(this);
     // This will cause all subpages to initially be hidden via dom-if.
     // This allows us to test loading each subpage independently without other
     // subpages affecting load times, etc.
     settingsHidePagesByDefaultForTest = true;
   },
 
-  /** @override */
-  setUp: function() {
-    SettingsPageBrowserTest.prototype.setUp.call(this);
-    this.verifySubPagesHidden_();
-  },
-
   /*
    * Checks all subpages are hidden first.
    * @private
    */
   verifySubPagesHidden_: function() {
-    var page = this.getPage(this.pageId);
+    var page = this.page;
     assertEquals(0, Object.keys(page.pageVisibility).length);
 
     // Ensure all pages are still hidden after the dom-ifs compute their |if|.
     Polymer.dom.flush();
     var sections = page.shadowRoot.querySelectorAll('settings-section');
     assertTrue(!!sections);
     assertEquals(0, sections.length);
   },
 
   /**
@@ skipping 11 matching lines @@
     Polymer.dom.flush();
     var dtime = window.performance.now() - startTime;
     console.log('Page: ' + subPage + ' Load time: ' + dtime.toFixed(0) + ' ms');
     assertTrue(!!this.getSection(page, subPage));
     // Hide the page so that it doesn't interfere with other subPages.
     page.set('pageVisibility.' + subPage, false);
     Polymer.dom.flush();
   },
 
   testSubPages: function() {
-    var page = this.getPage(this.pageId);
     this.subPages.forEach(function(subPage) {
-      test(subPage, this.testSubPage.bind(this, page, subPage));
+      test(subPage, function() {
+        this.verifySubPagesHidden_();
+        this.testSubPage.bind(this, this.page, subPage);

[Dan Beam, 2017/03/16 20:52:22]

this is not the same.  did you mean

this.testSubPage(this.page, subPage);

?

[dpapad, 2017/03/17 00:08:09]

Good catch. Yes, I meant what you wrote above. I'll address this in next patch.

+      }.bind(this));
     }.bind(this));
   },
 };
 
 /** @constructor @extends {SettingsSubPageBrowserTest} */
 function SettingsBasicSubPageBrowserTest() {
   SettingsSubPageBrowserTest.call(this, 'basic');
 
   /** @override */
   this.subPages = [
@@ skipping 45 matching lines @@
   setUp: function() {
     this.toggleAdvanced();
     SettingsSubPageBrowserTest.prototype.setUp.call(this);
   },
 };
 
 TEST_F('SettingsAdvancedSubPageBrowserTest', 'SubPages', function() {
   suite('Advanced', this.testSubPages.bind(this));
   mocha.run();
 });