Reset sync setup dialog to initial state when it is opened.

chrome/browser/resources/options/sync_setup_overlay.css

 /* TODO(jhawkins): Organize these by page. */
 
 #sync-setup-overlay * h4 {
   margin: 5px 0;
 }
 
 #sync-setup-overlay * form {
   -webkit-user-select: none;
 }
 
@@ skipping 85 matching lines @@
   margin: 4px 10px;
   vertical-align: middle;
   visibility: hidden;
 }
 
 #gaia-account-text {
   font-weight: bold;
 }
 
 #email-readonly {
-  display: none;
   font-weight: bold;
 }
 
 #sync-setup-overlay * div.errormsg {
   color: red;
-  display: none;
   font-size: smaller;
 }
 
 #passphrase-encryption-message {
   color: gray;
   margin-bottom: 5px;
 }
 
 #passphrase-input {
   margin-top: 5px;
@@ skipping 89 matching lines @@
   visibility: hidden;
   width: 70%;
 }
 
 #content-table {
   background-color: #fff;
   border: #c3d9ff 1px solid;
   padding: 2px;
 }
 
-.access-code-row {
-  display: none;
-}
-
 .access-code-row > td {
   padding-bottom: 1px;
   text-align: center;
 }
 
 #access-code-label-row > td {
   padding-top: 6px;
 }
 
-#error-custom {
-  display: none;
-}
-
-#captcha-div {
-  display: none;
-}
-
 #captcha-instructions {
   margin-bottom: 5px;
   white-space: normal;
 }
 
 #password-row {
   margin-top: 2px;
 }
 
 #action-area {
@@ skipping 74 matching lines @@
   display: none;
 }
 
 #learn-more-link {
   float: right;
 }
 
 html[dir='rtl'] #learn-more-link {
   float: left;
 }