Options: Remove the hidden class, since we override the hidden attribute to set

chrome/browser/resources/options/sync_setup_overlay.html

-<div id="sync-setup-overlay" class="page hidden">
-  <div id="sync-setup-login" class="hidden">
+<div id="sync-setup-overlay" class="page" hidden>
+  <div id="sync-setup-login" hidden>
     <h1 i18n-content="syncSetupOverlayTitle"></h1>
     <div class="content-area">
       <div>
         <div id="top-blurb-error">
           <span id="error-signing-in" i18n-content="errorSigningIn"></span>
           <span id="error-custom"></span>
         </div>
         <form id="gaia-login-form">
           <div id="gaia-login-box">
             <table id="content-table" cellspacing="0"
@@ skipping 169 matching lines @@
         </div>
       </div>
     </div>
     <div class="action-area">
       <div class="button-strip">
         <button id="sync-setup-cancel" type="reset" i18n-content="cancel">
         </button>
       </div>
     </div>
   </div>
-  <div id="sync-setup-configure" class="hidden">
+  <div id="sync-setup-configure" hidden>
     <div id="confirm-sync-preferences">
       <h1 i18n-content="confirmSyncPreferences"></h1>
       <div id="sync-instructions-container" class="content-area">
         <span i18n-content="chooseDataTypesInstructions"></span>
         <a i18n-values="href:encryptionHelpURL" target="_blank"
             i18n-content="learnMore"></a>
       </div>
       <div>
         <div class="action-area">
           <div class="action-area-link-container">
@@ skipping 151 matching lines @@
             </a>
           </div>
           <div id="choose-datatypes-throbber" class="throbber"></div>
           <input id="choose-datatypes-ok" type="submit" i18n-values="value:ok">
           <input id="choose-datatypes-cancel" type="button"
               i18n-values="value:cancel">
         </div>
       </form>
     </div>
   </div>
-  <div id="sync-setup-passphrase" class="hidden">
+  <div id="sync-setup-passphrase" hidden>
     <h1 i18n-content="enterPassphraseTitle"></h1>
     <div class="content-area">
       <form id="passphrase-form">
         <div id="enter-passphrase">
           <div id="normal-body" class="sync-instructions-start-hidden"
               i18n-content="enterPassphraseBody">
           </div>
           <div id="passphrase-rejected-body"
               class="sync-instructions-start-hidden"
               i18n-content="enterOtherPassphraseBody">
@@ skipping 18 matching lines @@
         </div>
       </form>
     </div>
     <div class="action-area">
       <div id="passphrase-throbber" class="throbber"></div>
       <input id="passphrase-ok" type="submit" i18n-values="value:ok">
       <input id="passphrase-cancel" type="button" i18n-values="value:cancel">
     </div>
   </div>
 </div>