Settings Router Refactor: Kill settings-router.

chrome/browser/resources/settings/settings_main/settings_main.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-main' displays the selected settings page.
  */
 Polymer({
   is: 'settings-main',
 
+  behaviors: [settings.RouteObserverBehavior],
+
   properties: {
     /**
      * Preferences state.
      */
     prefs: {
       type: Object,
       notify: true,
     },
 
-    /**
-     * The current active route.
-     * @type {!settings.Route}
-     */
-    currentRoute: {
-      type: Object,
-      notify: true,
-      observer: 'currentRouteChanged_',
-    },
-
     /** @private */
     advancedToggleExpanded_: {
       type: Boolean,
       value: false,
     },
 
     /** @private */
     inSubpage_: Boolean,
 
     /** @private */
@@ skipping 81 matching lines @@
   /**
    * @param {boolean} showBasicPage
    * @param {boolean} inSubpage
    * @return {boolean}
    * @private
    */
   showAdvancedToggle_: function(showBasicPage, inSubpage) {
     return showBasicPage && !inSubpage;
   },
 
-  /**
-   * @private
-   */
-  currentRouteChanged_: function(newRoute) {
+  /** @protected */
+  currentRouteChanged: function(newRoute) {
     this.inSubpage_ = newRoute.subpage.length > 0;
     this.style.height = this.inSubpage_ ? '100%' : '';
 
     if (settings.Route.ABOUT.contains(newRoute)) {
       this.showPages_ = {about: true, basic: false, advanced: false};
     } else {
       this.showPages_ = {
         about: false,
         basic: settings.Route.BASIC.contains(newRoute) || !this.inSubpage_,
         advanced: settings.Route.ADVANCED.contains(newRoute) ||
@@ skipping 18 matching lines @@
 
   /**
    * Return the height that the overscroll padding should be set to.
    * This is used to determine how much padding to apply to the end of the
    * content so that the last element may align with the top of the content
    * area.
    * @return {number}
    * @private
    */
   overscrollHeight_: function() {
-    if (!this.currentRoute || this.currentRoute.subpage.length != 0 ||
-        this.showPages_.about) {
+    var route = settings.getCurrentRoute();

[Dan Beam, 2016/08/05 18:25:19]

can |route| be falsy?

[tommycli, 2016/08/05 18:54:06]

Done.

+    if (!route || route.subpage.length != 0 || this.showPages_.about)
       return 0;
-    }
 
-    var query = 'settings-section[section="' + this.currentRoute.section + '"]';
+    var query = 'settings-section[section="' + route.section + '"]';
     var topSection = this.$$('settings-basic-page').$$(query);
     if (!topSection && this.showPages_.advanced)
       topSection = this.$$('settings-advanced-page').$$(query);
 
     if (!topSection || !topSection.offsetParent)
       return 0;
 
     // Offset to the selected section (relative to the scrolling window).
     let sectionTop = topSection.offsetParent.offsetTop + topSection.offsetTop;
     // The height of the selected section and remaining content (sections).
@@ skipping 53 matching lines @@
 
   /**
    * @param {(boolean|undefined)} visibility
    * @return {boolean} True unless visibility is false.
    * @private
    */
   showAdvancedSettings_: function(visibility) {
     return visibility !== false;
   },
 });