[MD settings] ripple on mouse down in side nav

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 52 matching lines @@
       this.$.advancedMenu.selected = null;
       // For routes from URL entry, we need to set selected.
       this.$.basicMenu.selected = newRoute.path;
     }
   },
 
   /**
    * @param {!Event} event
    * @private
    */
-  ripple_: function(event) {
-    var ripple = document.createElement('paper-ripple');
-    ripple.addEventListener('transitionend', function() {
-      ripple.remove();
-    });
-    event.currentTarget.appendChild(ripple);
-    ripple.downAction();
-    ripple.upAction();
-  },
-
-  /**
-   * @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);
   },
 
   /**
    * @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';
   },
 });