MD Settings: Fix missing yellow rectangle highlighting.

chrome/browser/resources/settings/search_settings.js

 // 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.
 
 cr.define('settings', function() {
   /** @const {string} */
   var WRAPPER_CSS_CLASS = 'search-highlight-wrapper';
 
   /** @const {string} */
   var HIT_CSS_CLASS = 'search-highlight-hit';
@@ skipping 84 matching lines @@
     // Use existing node as placeholder to determine where to insert the
     // replacement content.
     node.parentNode.replaceChild(wrapper, node);
 
     for (var i = 0; i < tokens.length; ++i) {
       if (i % 2 == 0) {
         wrapper.appendChild(document.createTextNode(tokens[i]));
       } else {
         var span = document.createElement('span');
         span.classList.add(HIT_CSS_CLASS);
+        span.style.backgroundColor = '#ffeb3b'; // --var(--paper-yellow-500)
         span.textContent = tokens[i];
         wrapper.appendChild(span);
       }
     }
   }
 
   /**
    * Traverses the entire DOM (including Shadow DOM), finds text nodes that
    * match the given regular expression and applies the highlight UI. It also
    * ensures that <settings-section> instances become visible if any matches
@@ skipping 461 matching lines @@
   function setSearchManagerForTesting(searchManager) {
     SearchManagerImpl.instance_ = searchManager;
   }
 
   return {
     getSearchManager: getSearchManager,
     setSearchManagerForTesting: setSearchManagerForTesting,
     SearchRequest: SearchRequest,
   };
 });