webui: make 0 into 0ms when it's a <time>.

chrome/common/extensions/docs/examples/api/fontSettings/css/overlay.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. */
 
 /* The shield that overlays the background. */
 .overlay {
   -webkit-box-align: center;
   -webkit-box-orient: vertical;
   -webkit-box-pack: center;
   -webkit-transition: 200ms opacity;
@@ skipping 25 matching lines @@
   color: #333;
   display: -webkit-box;
   min-width: 400px;
   padding: 0;
   position: relative;
 }
 
 /* If the options page is loading don't do the transition. */
 .loading .overlay,
 .loading .overlay .page {
-  -webkit-transition-duration: 0 !important;
+  -webkit-transition-duration: 0ms !important;
 }
 
 /* keyframes used to pulse the overlay */
 @-webkit-keyframes pulse {
  0% {
    -webkit-transform: scale(1);
  }
  40% {
    -webkit-transform: scale(1.02);
   }
@@ skipping 97 matching lines @@
 .overlay .page .content-area::-webkit-scrollbar-thumb {
   background-color: rgba(0, 0, 0, 0.2);
   border: 2px solid white;
   border-radius: 8px;
 }
 
 .overlay .page .content-area::-webkit-scrollbar-thumb:hover {
   background-color: rgba(0, 0, 0, 0.5);
 }
 </if>