MD Extensions: Convert classes to use ES6 class syntax.

chrome/browser/resources/md_extensions/animation_helper.js

 // Copyright 2016 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.
 
 cr.exportPath('extensions');
 
 /**
  * The different types of animations this helper supports.
  * @enum {number}
  */
 extensions.Animation = {
   HERO: 0,
   FADE_IN: 1,
   FADE_OUT: 2,
   SCALE_DOWN: 3,
 };
 
 cr.define('extensions', function() {
   'use strict';
 
   /**
    * A helper object for setting entry/exit animations. Polymer's support of
    * this is pretty limited, since it doesn't allow for things like specifying
    * hero properties or nodes.
-   * @param {!HTMLElement} element The parent element to set the animations on.
-   *     This will be used as the page in to/fromPage.
-   * @param {?HTMLElement} node The node to use for scaling and fading
-   *     animations.
-   * @constructor
    */
-  function AnimationHelper(element, node) {
-    this.element_ = element;
-    this.node_ = node;
-    element.animationConfig = {};
-  }
+  class AnimationHelper {
+    /**
+     * @param {!HTMLElement} element The parent element to set the animations
+     *     on. This will be used as the page in to/fromPage.
+     * @param {?HTMLElement} node The node to use for scaling and fading
+     *     animations.
+     */
+    constructor(element, node) {
+      this.element_ = element;
+      this.node_ = node;
+      element.animationConfig = {};
+    }
 
-  AnimationHelper.prototype = {
     /**
      * Set the entry animation for the element.
      * @param {!Array<extensions.Animation>} animations
      */
-    setEntryAnimations: function(animations) {
+    setEntryAnimations(animations) {
       var configs = [];
       for (let animation of animations) {
         switch (animation) {
           case extensions.Animation.HERO:
             configs.push(
                 {name: 'hero-animation', id: 'hero', toPage: this.element_});
             break;
           case extensions.Animation.FADE_IN:
             assert(this.node_);
             configs.push({name: 'fade-in-animation', node: this.node_});
             break;
           default:
             assertNotReached();
         }
       }
       this.element_.animationConfig.entry = configs;
-    },
+    }
 
     /**
      * Set the exit animation for the element.
      * @param {!Array<extensions.Animation>} animations
      */
-    setExitAnimations: function(animations) {
+    setExitAnimations(animations) {
       var configs = [];
       for (let animation of animations) {
         switch (animation) {
           case extensions.Animation.HERO:
             configs.push(
                 {name: 'hero-animation', id: 'hero', fromPage: this.element_});
             break;
           case extensions.Animation.FADE_OUT:
             assert(this.node_);
             configs.push({name: 'fade-out-animation', node: this.node_});
             break;
           case extensions.Animation.SCALE_DOWN:
             assert(this.node_);
             configs.push({
               name: 'scale-down-animation',
               node: this.node_,
               transformOrigin: '50% 50%',
               axis: 'y',
             });
             break;
           default:
             assertNotReached();
         }
       }
       this.element_.animationConfig.exit = configs;
-    },
-  };
+    }
+  }
 
   return {AnimationHelper: AnimationHelper};
 });