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

chrome/browser/resources/options/manage_profile_overlay.html

 <div id="manage-profile-overlay" class="page" hidden>
   <div class="close-button"></div>
   <!-- Dialog for managing profiles. -->
   <div id="manage-profile-overlay-manage" hidden>
     <h1 i18n-content="manageProfile"></h1>
     <div id="manage-profile-content" class="content-area">
       <div id="manage-profile-icon-label"
           i18n-content="manageProfilesIconLabel">
       </div>
       <grid id="manage-profile-icon-grid"></grid>
@@ skipping 85 matching lines @@
         </label>
       </div>
       <div id="create-profile-supervised-container" class="checkbox">
         <label>
           <input id="create-profile-supervised" type="checkbox">
           <span id="create-profile-supervised-signed-in">
             <span id="create-profile-supervised-signed-in-label"></span>
             <span id="create-profile-supervised-account-details-out-of-date-label"
                 hidden>
             </span>
-            <button id="create-profile-supervised-signed-in-learn-more-link"
-                class="link-button" i18n-content="learnMore">
-            </button>
-            <button id="create-profile-supervised-sign-in-again-link"
-                class="link-button"
-                i18n-content="manageProfilesSupervisedSignInAgainLink" hidden>
-            </button>
+            <a id="create-profile-supervised-signed-in-learn-more-link"
+                is="action-link" i18n-content="learnMore"></a>
+            <a id="create-profile-supervised-sign-in-again-link"
+                is="action-link"
+                i18n-content="manageProfilesSupervisedSignInAgainLink"
+                hidden></a>
           </span>
           <span id="create-profile-supervised-not-signed-in"
               i18n-values=".innerHTML:manageProfilesSupervisedNotSignedIn"
               hidden>
           </span>
         </label>
         <span id="create-profile-supervised-indicator"
             class="bubble-button controlled-setting-indicator">
         </span>
       </div>
       <div id="create-profile-error-bubble" hidden></div>
     </div>
     <div class="action-area">
       <div id="create-profile-throbber" class="throbber"></div>
-      <button id="import-existing-supervised-user-link" class="link-button"
-          i18n-content="importExistingSupervisedUserLink" hidden>
-      </button>
+      <a is="action-link" id="import-existing-supervised-user-link"
+          i18n-content="importExistingSupervisedUserLink" hidden></a>
       <div class="button-strip">
         <button id="create-profile-cancel" i18n-content="cancel"></button>
         <button id="create-profile-ok" i18n-content="createProfileConfirm"
             class="default-button">
         </button>
       </div>
     </div>
   </div>
 </div>