MD Settings: Eliminate use of ES6 for Chrome OS

chrome/browser/resources/settings/device_page/drag_behavior.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.
 
 /**
  * @fileoverview Behavior for handling dragging elements in a container.
  *     Draggable elements must have the 'draggable' attribute set.
  */
 
 /**
@@ skipping 63 matching lines @@
       this.container_ = opt_container;
 
     this.addListeners_();
 
     if (opt_callback !== undefined)
       this.callback_ = opt_callback;
   },
 
   /** @private */
   addListeners_: function() {
-    let container = this.container_;
+    var container = this.container_;
     if (!container || this.mouseDownListener_)
       return;
     this.mouseDownListener_ = this.onMouseDown_.bind(this);
     container.addEventListener('mousedown', this.mouseDownListener_);
 
     this.mouseMoveListener_ = this.onMouseMove_.bind(this);
     container.addEventListener('mousemove', this.mouseMoveListener_);
 
     this.touchStartListener_ = this.onTouchStart_.bind(this);
     container.addEventListener('touchstart', this.touchStartListener_);
 
     this.touchMoveListener_ = this.onTouchMove_.bind(this);
     container.addEventListener('touchmove', this.touchMoveListener_);
 
     this.endDragListener_ = this.endDrag_.bind(this);
     window.addEventListener('mouseup', this.endDragListener_);
     container.addEventListener('touchend', this.endDragListener_);
   },
 
   /** @private */
   removeListeners_: function() {
-    let container = this.container_;
+    var container = this.container_;
     if (!container || !this.mouseDownListener_)
       return;
     container.removeEventListener('mousedown', this.mouseDownListener_);
     this.mouseDownListener_ = null;
     container.removeEventListener('mousemove', this.mouseMoveListener_);
     this.mouseMoveListener_ = null;
     container.removeEventListener('touchstart', this.touchStartListener_);
     this.touchStartListener_ = null;
     container.removeEventListener('touchmove', this.touchMoveListener_);
     this.touchMoveListener_ = null;
@@ skipping 106 matching lines @@
     if (this.callback_) {
       var delta = {
         x: eventLocation.x - this.dragStartLocation_.x,
         y: eventLocation.y - this.dragStartLocation_.y,
       };
       this.callback_(this.dragId_, delta);
     }
     return false;
   },
 };