[MD settings] change ClearBrowsingData from a sub-page to a dialog

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">
   <template>
     <style>
       paper-dialog {
         max-width: 800px;
         min-width: 500px;
       }
 
       #dialog-content {
         -webkit-padding-end: 0;
         -webkit-padding-start: 0;
         margin-bottom: 0;
         margin-top: 0;
       }
 
       paper-dialog .top-row {
         align-items: center;
-        border-bottom: 1px solid gainsboro;
+        border-bottom: 1px solid var(--paper-grey-300);
         display: flex;
         padding-bottom: 5px;
         padding-top: 5px;
       }
 
+      paper-dialog .row {
+        align-items: center;
+        display: flex;
+        min-height: 40px;
+      }
+
+      paper-dialog .row .start {
+        flex: 1;
+      }
+
       paper-dialog .title {
         flex: 1;
         font-size: 1.13em;
       }
 
       paper-dialog .body {
         font-size: 1em;
         margin: 20px 0;
       }
 
       paper-dialog .title,
       paper-dialog .body {
         -webkit-padding-end: 24px;
         -webkit-padding-start: 24px;
       }
 
-      paper-dialog .cancel-button {
-        color: rgb(109, 109, 109);
+      paper-dialog .feedback-bar {
+        background-color: var(--paper-grey-200);
+        margin: 0;
+        padding: 20px;
+      }
+
+      paper-dialog .action-button {
+        -webkit-margin-start: 10px;
         font-weight: 500;
       }
 
+      paper-dialog .action-button:not([disabled]) {
+        background-color: var(--google-blue-500);
+        color: white;
+      }
+
+      paper-dialog .cancel-button {
+        color: var(--paper-grey-600);
+        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;
+        background-color: var(--paper-grey-300);
       }
     </style>
   </template>
 </dom-module>