Drop the -webkit prefix from user-select CSS rule in ui/.

ui/webui/resources/css/list.css

 /* 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. */
 
 list,
 grid {
   display: block;
   outline: none;
   overflow: auto;
   position: relative; /* Make sure that item offsets are relative to the
                          list. */
 }
 
 list > *,
 grid > * {
-  -webkit-user-select: none;
   background-color: rgba(255, 255, 255, 0);
   border: 1px solid rgba(255, 255, 255, 0); /* transparent white */
   border-radius: 2px;
   cursor: default;
   line-height: 20px;
   margin: -1px 0;
   overflow: hidden;
   padding: 0 3px;
   position: relative; /* to allow overlap */
   text-overflow: ellipsis;
+  user-select: none;
   white-space: pre;
 }
 
 list > * {
   display: block;
 }
 
 grid > * {
   display: inline-block;
 }
@@ skipping 76 matching lines @@
 }
 
 list > .drag-selection-border {
   border-radius: 0;
   background-color: rgba(255, 255, 255, 0.3);
   border: 2px solid rgba(255, 255, 255, 0.6);
   outline: 1px solid rgba(0, 0, 0, 0.1);
   position: absolute;
   z-index: 2;
 }