- Patch #440876 by Dave Reid, sun: reuse comment.module's anonymous cookie information.

modules/comment/comment.module

@@ -1645,7 +1645,7 @@ function comment_form($form, &$form_state, $comment) {
 
   if (!$user->uid && variable_get('comment_anonymous_' . $node->type, COMMENT_ANONYMOUS_MAYNOT_CONTACT) != COMMENT_ANONYMOUS_MAYNOT_CONTACT) {
     $form['#attached']['library'][] = array('system', 'cookie');
-    $form['#attached']['js'][] = drupal_get_path('module', 'comment') . '/comment.js';
+    $form['#attributes']['class'][] = 'user-info-from-cookie';
   }
 
   $comment = (array) $comment;

modules/contact/contact.pages.inc

@@ -50,7 +50,7 @@ function contact_site_form($form, &$form_state) {
 
   if (!$user->uid) {
     $form['#attached']['library'][] = array('system', 'cookie');
-    $form['#attached']['js'][] = drupal_get_path('module', 'contact') . '/contact.js';
+    $form['#attributes']['class'][] = 'user-info-from-cookie';
   }
 
   $form['#token'] = $user->uid ? $user->name . $user->mail : '';
@@ -178,7 +178,7 @@ function contact_personal_form($form, &$form_state, stdClass $recipient) {
 
   if (!$user->uid) {
     $form['#attached']['library'][] = array('system', 'cookie');
-    $form['#attached']['js'][] = drupal_get_path('module', 'contact') . '/contact.js';
+    $form['#attributes']['class'][] = 'user-info-from-cookie';
   }
 
   $form['#token'] = $user->uid ? $user->name . $user->mail : '';

modules/user/user.module

@@ -3068,6 +3068,9 @@ function user_register_form($form, &$form_state) {
   $form['#user'] = drupal_anonymous_user();
   $form['#user_category'] = 'register';
 
+  $form['#attached']['library'][] = array('system', 'cookie');
+  $form['#attributes']['class'][] = 'user-info-from-cookie';
+
   // Start with the default user account fields.
   user_account_form($form, $form_state);