MD Settings: Convert all usages of .bind(this) to use ES6 arrow function.

chrome/browser/resources/settings/internet_page/network_proxy.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 Polymer element for displaying and editing network proxy
  * values.
  */
 Polymer({
   is: 'network-proxy',
@@ skipping 199 matching lines @@
 
     this.setProxyAsync_(proxy);
   },
 
   /**
    * @param {!CrOnc.ProxySettings} proxy
    * @private
    */
   setProxyAsync_: function(proxy) {
     // Set this.proxy_ after dom-repeat has been stamped.
-    this.async(function() {
+    this.async(() => {
       this.proxy_ = proxy;
       this.proxyModified_ = false;
-    }.bind(this));
+    });
   },
 
   /** @private */
   useSameProxyChanged_: function() {
     this.proxyModified_ = true;
   },
 
   /** @private */
   useSharedProxiesChanged_: function() {
     var pref = this.getPref('settings.use_shared_proxies');
@@ skipping 254 matching lines @@
     /** @type {!SettingsCheckboxElement} */ (this.$.allowShared)
         .resetToPrefValue();
     this.$.confirmAllowSharedDialog.close();
   },
 
   /** @private */
   onAllowSharedDialogClose_: function() {
     cr.ui.focusWithoutInk(assert(this.$$('#allowShared')));
   },
 });