[MD settings] side nav routing to page sections

chrome/browser/resources/settings/settings_page/settings_animated_pages.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-animated-pages' is a container for a page and animated subpages.
  * It provides a set of common behaviors and animations.
  *
  * Example:
@@ skipping 70 matching lines @@
 
   /** @private */
   currentRouteChanged_: function(newRoute, oldRoute) {
     // Don't manipulate the light DOM until it's ready.
     if (!this.lightDomReady_) {
       this.queuedRouteChange_ = this.queuedRouteChange_ || {oldRoute: oldRoute};
       this.queuedRouteChange_.newRoute = newRoute;
       return;
     }
 
-    // route.section is only non-empty when the user is within a subpage.
-    // When the user is not in a subpage, but on the Basic page, route.section
-    // is an empty string.
-    var newRouteIsSubpage = newRoute && newRoute.section == this.section;
-    var oldRouteIsSubpage = oldRoute && oldRoute.section == this.section;
+    var newRouteIsSubpage = newRoute && newRoute.subpage.length;
+    var oldRouteIsSubpage = oldRoute && oldRoute.subpage.length;
 
     if (newRouteIsSubpage)
       this.ensureSubpageInstance_();
 
     if (!newRouteIsSubpage || !oldRouteIsSubpage ||
         newRoute.subpage.length == oldRoute.subpage.length) {
       // If two routes are at the same level, or if either the new or old route
       // is not a subpage, fade in and out.
       this.$.animatedPages.exitAnimation = 'fade-out-animation';
       this.$.animatedPages.entryAnimation = 'fade-in-animation';
@@ skipping 41 matching lines @@
    * Buttons in this pageset should use this method to transition to subpages.
    */
   setSubpageChain: function(subpage) {
     this.currentRoute = {
       page: this.currentRoute.page,
       section: subpage.length > 0 ? this.section : '',
       subpage: subpage,
     };
   },
 });