Settings Router Refactor: Allow no-op navigations.

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.
 
 /**
  * @typedef {{about: boolean, basic: boolean, advanced: boolean}}
  */
 var MainPageVisibility;
 
 /**
@@ skipping 186 matching lines @@
   /** @private */
   toggleAdvancedPage_: function() {
     this.fire('toggle-advanced-page', !this.advancedToggleExpanded_);
   },
 
   /**
    * Navigates to the default search page (if necessary).
    * @private
    */
   ensureInDefaultSearchPage_: function() {
-    settings.navigateTo(settings.Route.BASIC);
+    if (settings.getCurrentRoute() != settings.Route.BASIC)
+      settings.navigateTo(settings.Route.BASIC);
   },
 
   /**
    * @param {string} query
    * @return {!Promise} A promise indicating that searching finished.
    */
   searchContents: function(query) {
     if (!this.previousShowPages_) {
       // Store which pages are shown before search, so that they can be restored
       // after the user clears the search results.
@@ skipping 41 matching lines @@
 
   /**
    * @param {(boolean|undefined)} visibility
    * @return {boolean} True unless visibility is false.
    * @private
    */
   showAdvancedSettings_: function(visibility) {
     return visibility !== false;
   },
 });