Add controlled setting indicator for default search engine configuration

chrome/browser/resources/options/browser_options.html

 <div id="settings" class="page" hidden>
   <header>
     <h1 i18n-content="settingsTitle"></h1>
   </header>
 <if expr="not pp_ifdef('chromeos')">
   <include src="sync_section.html">
 </if>
 <if expr="pp_ifdef('chromeos')">
   <section>
     <h3 i18n-content="sectionTitleInternet"></h3>
@@ skipping 107 matching lines @@
   </section>
 </if>
   <section>
     <h3 i18n-content="sectionTitleSearch"></h3>
       <div>
         <span class="settings-row"
             i18n-values=".innerHTML:defaultSearchGroupLabel">
         </span>
         <div class="settings-row">
           <select id="default-search-engine" class="weakrtl"></select>
+          <span class="controlled-setting-indicator"
+              pref="default_search_provider.enabled">
+          </span>
           <button id="manage-default-search-engines"
               i18n-content="defaultSearchManageEngines">
           </button>
         </div>
         <div class="checkbox" guest-visibility="disabled">
           <label id="instant-label">
             <!-- TODO(estade): metric? -->
             <input id="instant-enabled-control" type="checkbox"
                 pref="instant.enabled">
             <!-- TODO(estade) There's a link in here which should not be inside
@@ skipping 478 matching lines @@
   </section>
 </if>
 </div>  <!-- advanced-settings-container -->
 </div>  <!-- advanced-settings -->
 <footer>
   <button id="advanced-settings-expander" class="link-button"
       i18n-content="showAdvancedSettings">
   </button>
 </footer>
 </div>