MD Settings: Remove some ES6 leftovers from CrOS code that break uglify.

chrome/browser/resources/settings/bluetooth_page/bluetooth_page.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-bluetooth-page' is the settings page for managing bluetooth
  *  properties and devices.
  *
  * Example:
@@ skipping 569 matching lines @@
       this.updateDeviceList_();
     }.bind(this));
   },
 
   /**
    * @param {string} dialogId
    * @param {string} dialogToShow The name of the dialog.
    * @return {boolean}
    * @private
    */
-  dialogIsVisible_(dialogId, dialogToShow) {
+  dialogIsVisible_: function(dialogId, dialogToShow) {
     return dialogToShow == dialogId;
   },
 
   /**
    * @param {string} dialogId
    * @private
    */
   openDialog_: function(dialogId) {
     if (this.dialogId_) {
       // Dialog already opened, just update the contents.
@@ skipping 17 matching lines @@
   },
 
   /**
    * @param {Event} e
    * @private
    */
   stopTap_: function(e) {
     e.stopPropagation();
   },
 });