Reduce usage of webkit CSS prefixes in chrome/browser/resources

chrome/browser/resources/chromeos/login/header_bar.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. */
 
 #login-header-bar {
   -webkit-padding-start: 15px;
   bottom: 0;
   left: 0;
   padding-bottom: 6px;
   position: absolute;
   right: 0;
 }
 
 #login-header-bar {
   background-color: rgba(0, 0, 0, 0.6);
   padding-top: 7px;
 }
 
 html[screen=lock] .login-header-bar-hidden,
 html[screen=oobe] .login-header-bar-hidden {
   opacity: 0;
 }
 
 html[screen=lock] .login-header-bar-animate-fast,
 html[screen=oobe] .login-header-bar-animate-fast {
-  -webkit-transition: opacity 200ms ease-out;
+  transition: opacity 200ms ease-out;
 }
 
 html[screen=lock] .login-header-bar-animate-slow,
 html[screen=oobe] .login-header-bar-animate-slow {
-  -webkit-transition: opacity 2s ease-out;
+  transition: opacity 2s ease-out;
 }
 
 #login-header-bar button,
 #login-header-bar button:active,
 #login-header-bar button:focus,
 #login-header-bar button:hover {
   background: transparent none;
   box-shadow: none;
   cursor: pointer;
   height: 34px;
@@ skipping 114 matching lines @@
   background-image: -webkit-image-set(
       url(images/1x/signout.svg) 1x,
       url(images/2x/signout.svg) 2x );
 }
 
 .button-restricted {
   border: 1px solid transparent;
   color: white !important;
   opacity: 0.4 !important;
 }