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

chrome/browser/resources/settings/appearance_page/appearance_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.
 
 
 /**
  * This is the absolute difference maintained between standard and
  * fixed-width font sizes. http://crbug.com/91922.
  * @const @private {number}
  */
@@ skipping 122 matching lines @@
   /** @override */
   created: function() {
     this.browserProxy_ = settings.AppearanceBrowserProxyImpl.getInstance();
   },
 
   /** @override */
   ready: function() {
     this.$.defaultFontSize.menuOptions = this.fontSizeOptions_;
     // TODO(dschuyler): Look into adding a listener for the
     // default zoom percent.
-    this.browserProxy_.getDefaultZoom().then(function(zoom) {
+    this.browserProxy_.getDefaultZoom().then(zoom => {
       this.defaultZoom_ = zoom;
-    }.bind(this));
+    });
   },
 
   /**
    * @param {number} zoom
    * @return {number} A zoom easier read by users.
    * @private
    */
   formatZoom_: function(zoom) {
     return Math.round(zoom * 100);
   },
@@ skipping 108 matching lines @@
 
   /**
    * @param {string} themeId
    * @param {boolean} useSystemTheme
    * @private
    */
   themeChanged_: function(themeId, useSystemTheme) {
     if (themeId) {
       assert(!useSystemTheme);
 
-      this.browserProxy_.getThemeInfo(themeId).then(function(info) {
+      this.browserProxy_.getThemeInfo(themeId).then(info => {
         this.themeSublabel_ = info.name;
-      }.bind(this));
+      });
 
       this.themeUrl_ = 'https://chrome.google.com/webstore/detail/' + themeId;
       return;
     }
 
     var i18nId;
     // <if expr="is_linux and not chromeos">
     i18nId = useSystemTheme ? 'systemTheme' : 'classicTheme';
     // </if>
     // <if expr="not is_linux or chromeos">
@@ skipping 21 matching lines @@
    * @see content::ZoomValuesEqual().
    * @param {number} zoom1
    * @param {number} zoom2
    * @return {boolean}
    * @private
    */
   zoomValuesEqual_: function(zoom1, zoom2) {
     return Math.abs(zoom1 - zoom2) <= 0.001;
   },
 });