Add <a is="action-link">, a web component extension of <a> for in-page actions.

chrome/browser/resources/options/sync_section.html

 <if expr="not chromeos">
 <section id="sync-section">
   <h3 i18n-content="sectionTitleSync"></h3>
 </if>
 <if expr="chromeos">
 <div id="sync-section">
 </if>
 
   <div id="sync-overview" class="settings-row" hidden>
     <p i18n-content="syncOverview"></p>
     <a i18n-values="href:syncLearnMoreURL" i18n-content="learnMore"
         target="_blank"></a>
   </div>
 
 <if expr="chromeos">
   <div id="account-picture-wrapper">
     <div id="account-picture-control">
       <input type="image" id="account-picture" tabindex="0"
           alt="" i18n-values="aria-label:changePicture">
       <div id="change-picture-caption" i18n-content="changePicture"></div>
     </div>
     <span id="account-picture-indicator" class="controlled-setting-indicator">
     </span>
   </div>
   <div id="sync-general">
 </if>  <!-- chromeos -->
 
     <div id="sync-status" class="settings-row" hidden>
       <span id="sync-status-text"></span>
-      <button id="sync-action-link" class="link-button"></button>
+      <a is="action-link" id="sync-action-link"></a>
     </div>
 
 <if expr="chromeos">
     <div class="checkbox controlled-setting-with-label"
         public-account-visibility="hidden">
       <label>
         <input type="checkbox"
             metric="Options_ScreenLock"
             pref="settings.enable_screen_lock">
        <span>
@@ skipping 22 matching lines @@
     </button>
 </if>  <!-- chromeos -->
   </div>
 
 <if expr="not chromeos">
 </section>
 </if>
 <if expr="chromeos">
 </div>
 </if>