[MD settings] using h2 for sub-headers consistently.

chrome/browser/resources/settings/search_engines_page/search_engines_list.html

 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-list/iron-list.html">
 <link rel="import" href="chrome://resources/cr_elements/shared_style_css.html">
 <link rel="import" href="/search_engines_page/search_engine_entry.html">
 
 <dom-module id="settings-search-engines-list">
   <template>
     <style include="cr-shared-style">
       .headers {
         display: flex;
         padding: 10px 0;
       }
 
       .headers .name,
       .headers .keyword {
         flex: 3;
       }
 
       .headers .url {
         flex: 4.5;
       }
 
       div#outer {
-        margin: var(--search-engines-list-margin);
+        @apply(--settings-list-frame-padding);
       }
 
-      ::content [is='action-link'] {
-        margin: var(--search-engines-list-item-vertical-space) 0;
+      settings-search-engine-entry {
+        border-top: var(--settings-separator-line);
+      }
+
+      settings-search-engine-entry:first-of-type {
+        border-top: none;
       }
     </style>
     <div id="outer">
       <content></content>
       <iron-list items="[[engines]]" selectable>
         <template>
           <settings-search-engine-entry engine="[[item]]"
               tabindex$="[[tabIndex]]">
           </settings-search-engine-entry>
         </template>
       </iron-list>
     </div>
   </template>
   <script src="search_engines_list.js"></script>
 </dom-module>