Reduce webkit CSS prefixes in ui/ styles

ui/webui/resources/css/widgets.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. */
 
 /* This file defines styles for form controls. The order of rule blocks is
  * important as there are some rules with equal specificity that rely on order
  * as a tiebreaker. These are marked with OVERRIDE. */
 
 @import url(action_link.css);
 
@@ skipping 217 matching lines @@
     input[type='radio'],
     input[type='search'],
     input[type='text'],
     input[type='url'],
     input:not([type]),
     :-webkit-any(
          button,
          input[type='button'],
          input[type='submit']):not(.custom-appearance)) {
   /* OVERRIDE */
-  -webkit-transition: border-color 200ms;
+  transition: border-color 200ms;
   /* We use border color because it follows the border radius (unlike outline).
    * This is particularly noticeable on mac. */
   border-color: rgb(77, 144, 254);
   outline: none;
 }
 
 /* Checkbox/radio helpers ******************************************************
  *
  * .checkbox and .radio classes wrap labels. Checkboxes and radios should use
  * these classes with the markup structure:
@@ skipping 31 matching lines @@
 
 label > input:disabled:-webkit-any([type='checkbox'], [type='radio']) ~ span {
   color: #999;
 }
 
 extensionview {
   display: inline-block;
   height: 300px;
   width: 300px;
 }