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

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

 <link rel="import" href="chrome://resources/html/action_link.html">
 <link rel="import" href="chrome://resources/html/cr.html">
 <link rel="import" href="chrome://resources/html/polymer.html">
 <link rel="import" href="chrome://resources/cr_elements/cr_expand_button/cr_expand_button.html">
 <link rel="import" href="chrome://resources/polymer/v1_0/iron-collapse/iron-collapse.html">
 <link rel="import" href="chrome://resources/html/web_ui_listener_behavior.html">
 <link rel="import" href="/search_engines_page/search_engines_browser_proxy.html">
 <link rel="import" href="/search_engines_page/search_engine_dialog.html">
 <link rel="import" href="/search_engines_page/search_engines_list.html">
 <link rel="import" href="/search_engines_page/omnibox_extension_entry.html">
 <link rel="import" href="/settings_shared_css.html">
 
 <dom-module id="settings-search-engines-page">
   <link rel="import" type="css" href="chrome://resources/css/action_link.css">
   <template>
     <style include="settings-shared">
       :host {
         --search-engines-list-item-vertical-space: 8px;
-        --search-engines-list-margin: 0 40px;
+        --search-engines-list-margin: 0 36px;
       }
-      .label {
-        margin: 20px;
-      }
+
       .extension-engines {
         margin: var(--search-engines-list-margin);
       }
     </style>
-    <div>
-      <div class="label">$i18n{searchEnginesDefault}</div>
+    <div class="settings-box block">

[hcarmona, 2016/08/24 23:41:21]

This is adding a dividing line between the header and this list.
Is this expected?

[dschuyler, 2016/08/25 02:00:53]

Ah, I changed this in the next CL, but it should be in this CL

+      <h2>$i18n{searchEnginesDefault}</h2>
       <settings-search-engines-list engines="[[defaultEngines]]">
       </settings-search-engines-list>
     </div>
     <template is="dom-if" if="[[showAddSearchEngineDialog_]]" restamp>
       <settings-search-engine-dialog></settings-search-engine-dialog>
     </template>
-    <div>
-      <div class="label">$i18n{searchEnginesOther}</div>
+    <div class="settings-box block">

[hcarmona, 2016/08/24 23:41:21]

Same here for a dividing line between the lists.

[dschuyler, 2016/08/25 02:00:53]

I think a line makes sense here. I haven't found mocks for this though.

+      <h2>$i18n{searchEnginesOther}</h2>
       <!-- TODO(dbeam): why does on-click work with keyboard but on-tap
            doesn't? -->
       <settings-search-engines-list engines="[[otherEngines]]">
         <a is="action-link" on-tap="onAddSearchEngineTap_" id="addSearchEngine">
             $i18n{searchEnginesAddSearchEngine}</a>
       </settings-search-engines-list>
 
       <template is="dom-if" if="[[showExtensionsList_]]">
-        <div class="label">$i18n{searchEnginesExtension}</div>
+        <h2>$i18n{searchEnginesExtension}</h2>
         <iron-list items="[[extensions]]" class="extension-engines" selectable>
           <template>
             <settings-omnibox-extension-entry engine="[[item]]"
                 tabindex$="[[tabIndex]]">
             </settings-omnibox-extension-entry>
           </template>
         </iron-list>
       </template>
     </div>
   </template>
   <script src="search_engines_page.js"></script>
 </dom-module>