Adds in-out easing type.

chrome/browser/resources/vr_shell/vr_shell_ui.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.
 
 var vrShellUi = (function() {
   'use strict';
 
   let ui = new scene.Scene();
   let uiManager;
   let nativeCommandHandler;
@@ skipping 91 matching lines @@
         y = this.MENU_MODE_SCREEN_ELEVATION;
         distance = this.MENU_MODE_SCREEN_DISTANCE;
         height = this.MENU_MODE_SCREEN_HEIGHT;
       } else if (this.fullscreen) {
         distance = this.FULLSCREEN_DISTANCE;
       }
 
       let anim;
       anim = new api.Animation(this.elementId, ANIM_DURATION);
       anim.setTranslation(0, y, -distance);
+      anim.setEasing(new api.InOutEasing());
       ui.addAnimation(anim);
       anim = new api.Animation(this.elementId, ANIM_DURATION);
       anim.setSize(height * this.SCREEN_RATIO, height);
+      anim.setEasing(new api.InOutEasing());
       ui.addAnimation(anim);
 
       ui.setBackgroundDistance(distance * this.BACKGROUND_DISTANCE_MULTIPLIER);
     }
 
     // TODO(crbug/643815): Add a method setting aspect ratio (and possible
     // animation of changing it).
 
     getElementId() {
       return this.elementId;
@@ skipping 841 matching lines @@
     nativeCommandHandler.handleCommand(dict);
   }
 
   return {
     initialize: initialize,
     command: command,
   };
 })();
 
 window.addEventListener('load', vrShellUi.initialize);