[webui] get rid of more html[os=] rules

chrome/browser/resources/print_preview/print_preview.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.
  */
 
 html {
   height: 100%;
 }
 
 body {
@@ skipping 381 matching lines @@
 .message-with-dots span span:nth-child(3) {
   -webkit-animation-delay: 300ms;
 }
 
 #error-action-area {
   margin-top: 10px;
 }
 
 /* TODO(estade): unfork this code. */
 .button-strip {
+<if expr="not pp_ifdef('toolkit_views')">
+  -webkit-box-direction: reverse;
+</if>
   -webkit-box-orient: horizontal;
   -webkit-box-pack: end;
   display: -webkit-box;
 }
 
-html:not([toolkit=views]) .button-strip {
-  -webkit-box-direction: reverse;
-}
-
 #print-preview .button-strip button {
   -webkit-margin-start: 4px;
   display: block;
 }
 
 #dummy-box {
   -webkit-box-align: stretch;
   -webkit-box-flex: 1;
   -webkit-box-orient: vertical;
   background: #ccc;
@@ skipping 24 matching lines @@
 }
 
 #intentionally-blank {
   color: black;
   display: inline-block;
   font-style: italic;
   text-align: center;
   text-decoration: none;
   padding: 0 10px;
 }