Reduce usage of webkit prefixes in extension examples

chrome/common/extensions/docs/examples/api/fontSettings/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.
  */
 
@@ skipping 108 matching lines @@
   -webkit-user-select: none;
   background-image: url('../images/check.png');
   background-size: 100% 100%;
   content: '';
   display: block;
   height: 100%;
   width: 100%;
 }
 
 html[dir='rtl'] input[type='checkbox']:checked::before {
-  -webkit-transform: scaleX(-1);
+  transform: scaleX(-1);
 }
 
 input[type='radio']:checked::before {
   background-color: #666;
   border-radius: 100%;
   bottom: 3px;
   content: '';
   display: block;
   left: 3px;
   position: absolute;
@@ skipping 87 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):not(.link-button)) {
   /* 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;
 }
 
 /* Link buttons ***************************************************************/
 
 .link-button {
   -webkit-box-shadow: none;
@@ skipping 49 matching lines @@
   display: block;
 }
 
 :-webkit-any(.checkbox, .radio) label:hover {
   color: black;
 }
 
 label > input:disabled:-webkit-any([type='checkbox'], [type='radio']) ~ span {
   color: #999;
 }