fix appearance of buttons in chrome://settings

chrome/browser/resources/options/search_engine_manager_engine_list.js

 // Copyright (c) 2011 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.
 
 cr.define('options.search_engines', function() {
   const InlineEditableItemList = options.InlineEditableItemList;
   const InlineEditableItem = options.InlineEditableItem;
   const ListSelectionController = cr.ui.ListSelectionController;
 
   /**
@@ skipping 104 matching lines @@
       var urlEl = this.createEditableTextCell(engine['url']);
       var urlWithButtonEl = this.ownerDocument.createElement('div');
       urlWithButtonEl.appendChild(urlEl);
       urlWithButtonEl.className = 'url-column';
       urlWithButtonEl.classList.add('weakrtl');
       this.contentElement.appendChild(urlWithButtonEl);
       // Add the Make Default button. Temporary until drag-and-drop re-ordering
       // is implemented. When this is removed, remove the extra div above.
       if (engine['canBeDefault']) {
         var makeDefaultButtonEl = this.ownerDocument.createElement('button');
-        makeDefaultButtonEl.className = "raw-button";
+        makeDefaultButtonEl.className = 'raw-button custom-appearance';
         makeDefaultButtonEl.textContent =
             templateData.makeDefaultSearchEngineButton;
         makeDefaultButtonEl.onclick = function(e) {
           chrome.send('managerSetDefaultSearchEngine', [engine['modelIndex']]);
         };
         // Don't select the row when clicking the button.
         makeDefaultButtonEl.onmousedown = function(e) {
           e.stopPropagation();
         };
         urlWithButtonEl.appendChild(makeDefaultButtonEl);
@@ skipping 171 matching lines @@
     },
   };
 
   // Export
   return {
     SearchEngineList: SearchEngineList
   };
 
 });