MD Settings: create a global "action button" style (blue, flat)

chrome/browser/resources/settings/settings_dialog_css.html

 /* Copyright 2016 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. */
 
 /**
  * @fileoverview
  * Common dialog styles for Material Design settings.
  */
 
 <dom-module id="settings-dialog">
@@ skipping 28 matching lines @@
         font-size: 1em;
         margin: 20px 0;
       }
 
       paper-dialog .title,
       paper-dialog .body {
         -webkit-padding-end: 24px;
         -webkit-padding-start: 24px;
       }
 
-      paper-dialog .action-button {
-        -webkit-margin-start: 10px;
-        font-weight: 500;
-      }
-
-      paper-dialog .action-button:not([disabled]) {
-        background-color: rgb(66, 133, 244);
-        color: white;
-      }
-
       paper-dialog .cancel-button {
         color: rgb(109, 109, 109);
         font-weight: 500;
       }
 
       paper-dialog .explanation {
         margin-bottom: 35px;
       }
 
       paper-dialog .button-container {
         display: flex;
         justify-content: flex-end;
       }
 
       paper-dialog paper-button {
         margin: 0;
         min-width: auto;
       }
 
       paper-dialog paper-button[toggles][active] {
         background-color: LightGray;
       }
     </style>
   </template>
 </dom-module>