[MD settings] idle load basic and advanced pages

chrome/browser/resources/settings/basic_page/basic_page.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
  * 'settings-basic-page' is the settings page containing the actual settings.
  */
 Polymer({
   is: 'settings-basic-page',
@@ skipping 11 matching lines @@
 
     /**
      * Dictionary defining page visibility.
      * @type {!GuestModePageVisibility}
      */
     pageVisibility: Object,
 
     advancedToggleExpanded: {
       type: Boolean,
       notify: true,
+      observer: 'advancedToggleExpandedChanged_',
     },
 
     /**
      * True if a section is fully expanded to hide other sections beneath it.
      * False otherwise (even while animating a section open/closed).
      * @private {boolean}
      */
     hasExpandedSection_: {
       type: Boolean,
       value: false,
@@ skipping 52 matching lines @@
    * @param {string} query The text to search for.
    * @return {!Promise<!settings.SearchRequest>} A signal indicating that
    *     searching finished.
    */
   searchContents: function(query) {
     var whenSearchDone = settings.getSearchManager().search(
         query, assert(this.$$('#basicPage')));
 
     if (this.pageVisibility.advancedSettings !== false) {
       assert(whenSearchDone === settings.getSearchManager().search(
-          query, assert(this.$$('#advancedPage'))));
+          query, assert(this.$.advancedPageTemplate.get())));

[Dan Beam, 2017/02/02 01:00:50]

could this assert() fail?

[dschuyler, 2017/02/02 02:28:15]

My expectation is that it will fail or succeed in the same conditions as it did
before this CL. So I believe it would fail (before this CL and with this CL) if
the basic page dom-if template were not expanded. The failures should line up
with common uses of assert, meaning that if it fails it's because something is
wrong and should be fixed (it's helping detect an error). I'm not seeing where
it could cause a false positive.

[dpapad, 2017/02/02 02:34:33]

My understanding is that this assert is a left-over since before the advanced
page was behind a cr-lazy-render (used a plain dom-if instead), and it existed
to make the compiler happy. As it stands now, I don't think this assert can ever
fail, nor is it needed to satisfy the compiler anymore.

     }
 
     return whenSearchDone;
   },
 
   /** @private */
   onResetDone_: function() {
     this.showResetProfileBanner_ = false;
   },
 
   /**
    * @return {boolean}
    * @private
    */
   shouldShowAndroidApps_: function() {
     var visibility = /** @type {boolean|undefined} */ (
         this.get('pageVisibility.androidApps'));
     return this.showAndroidApps && this.showPage(visibility);
   },
 
   /**
    * Hides everything but the newly expanded subpage.
    * @private
    */
   onSubpageExpanded_: function() {
     this.hasExpandedSection_ = true;
   },
 
   /**
+   * Render the advanced page now (don't wait for idle).
+   * @private
+   */
+  advancedToggleExpandedChanged_: function() {
+    if (this.advancedToggleExpanded)
+      this.$.advancedPageTemplate.get();
+  },
+
+  /**
    * @param {boolean} inSearchMode
    * @param {boolean} hasExpandedSection
    * @return {boolean}
    * @private
    */
   showAdvancedToggle_: function(inSearchMode, hasExpandedSection) {
     return !inSearchMode && !hasExpandedSection;
   },
 
   /**
@@ skipping 35 matching lines @@
 
   /**
    * @param {boolean} opened Whether the menu is expanded.
    * @return {string} Icon name.
    * @private
    */
   getArrowIcon_: function(opened) {
     return opened ? 'cr:arrow-drop-up' : 'cr:arrow-drop-down';
   },
 });