MD Settings: Preserve search URL param in subpages.

chrome/browser/resources/settings/settings_menu/settings_menu.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-menu' shows a menu with a hardcoded set of pages and subpages.
  */
 Polymer({
   is: 'settings-menu',
@@ skipping 57 matching lines @@
     }
   },
 
   /**
    * @param {!Event} event
    * @private
    */
   openPage_: function(event) {
     var route = settings.getRouteForPath(event.currentTarget.dataset.path);
     assert(route, 'settings-menu has an an entry with an invalid path');
-    settings.navigateTo(route);
+    settings.navigateTo(route, null, false);

[dschuyler, 2016/11/09 23:10:14]

I find null, false unclear. Could we do

settings.navigateTo(route, /*dynamicParams*/null, /*preserveSearch*/false);

or 

settings.navigateTo(route, new URLSearchParams(), /*preserveSearch*/false);

[dpapad, 2016/11/09 23:19:16]

Done.

   },
 
   /**
    * @param {boolean} opened Whether the menu is expanded.
    * @return {string} Which icon to use.
    * @private
    * */
   arrowState_: function(opened) {
     return opened ? 'settings:arrow-drop-up' : 'cr:arrow-drop-down';
   },
 });