[web_dev_style] Changing :pseudo-element to ::pseudo-element to match

chrome/browser/resources/file_manager/css/common.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 contains "borrowed" copy of standard styles. To simplify merging,
- * when altering, please preserve original property value by adding comments.
- */
+ * when altering, please preserve original property value by adding comments. */
 input.common[type='checkbox'],
 input.common[type='radio'] {
   -webkit-appearance: none;
   -webkit-border-radius: 1px;
   -webkit-box-sizing: border-box;
   border: 1px solid #555;
   border-radius: 1px;
   box-sizing: border-box;
   cursor: default;
   height: 13px;
@@ skipping 18 matching lines @@
     url('../images/common/check_no_box.png') 1x,
     url('../images/common/2x/check_no_box.png') 2x);
   background-position: -3px -4px;
   background-repeat: no-repeat;
 }
 
 input.common[type='checkbox'].white {
   border: none;
 }
 
-input.common[type='checkbox'].white:not(:checked):after {
+input.common[type='checkbox'].white:not(:checked)::after {
   background-image: -webkit-image-set(
     url('../images/common/checkbox_white_unchecked.png') 1x,
     url('../images/common/2x/checkbox_white_unchecked.png') 2x);
   background-position: -1px 0;
 }
 
 input.common[type='checkbox'].white:checked::after {
   background-image: -webkit-image-set(
     url('../images/common/checkbox_white_checked.png') 1x,
     url('../images/common/2x/checkbox_white_checked.png') 2x);
@@ skipping 244 matching lines @@
   margin: 2px 0;
 }
 
 menu.chrome-menu > :not(hr)[checked] {
   background-image: -webkit-image-set(
     url('../images/common/check_no_box.png') 1x,
     url('../images/common/2x/check_no_box.png') 2x);
   background-position: 2px center;
 }
 
-menu.chrome-menu > [checked]:before {
+menu.chrome-menu > [checked]::before {
   display: none;
 }
 
 /* Ok/Cancel style buttons */
 button,
 input[type='button'],
 input[type='submit'],
 select {
   -webkit-border-radius: 2px;
   -webkit-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
@@ skipping 29 matching lines @@
 input[type='button'][disabled],
 input[type='submit'][disabled],
 button[disabled]:hover,
 input[type='button'][disabled]:hover,
 input[type='submit'][disabled]:hover {
   -webkit-box-shadow: none;
   background: -webkit-linear-gradient(#fafafa, #f4f4f4 40%, #e5e5e5);
   border-color: #aaa;
   color: #888;
 }