Prevent dragging in open/save dialogs.

chrome/browser/resources/file_manager/js/file_transfer_controller.js

 // Copyright (c) 2012 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 MAX_DRAG_THUMBAIL_COUNT = 4;
 
 function FileTransferController(fileList,
                                 fileListSelection,
                                 dragNodeConstructor,
                                 copyManager,
@@ skipping 21 matching lines @@
 
 }
 
 FileTransferController.prototype = {
   __proto__: cr.EventTarget.prototype,
 
   /**
    * @param {cr.ui.List} list Items in the list will be draggable.
    */
   attachDragSource: function(list) {
+    list.style.webkitUserDrag = 'element';
     list.addEventListener('dragstart', this.onDragStart_.bind(this, list));
     list.addEventListener('dragend', this.onDragEnd_.bind(this, list));
     list.addEventListener('drag', this.onDrag_.bind(this, list));
   },
 
   /**
    * @param {cr.ui.List} list List itself and its directory items will could
    *                          be drop target.
    */
   attachDropTarget: function(list) {
@@ skipping 344 matching lines @@
    * @type {Array.<Entry>}
    */
   get selectedEntries_() {
     var list = this.fileList_;
     return this.fileListSelection_.selectedIndexes.map(function(index) {
       return list.item(index);
     });
   }
 };