Access control: allow viewing of nodes of a certain type

This is directly based on this patch. It adds a 'view content_foo content' option to the Access Control page. I'd submit a patch but it doesn't quite work yet: I couldn't figure out how to exclude Search results that the user doesn't have access to. Is this possible?

Here are the changes:

Add to content_perm()

$perms[] = 'view '. $name .' content';

and add to content_access($op, $node)

  if ($op == 'view') {
    return user_access('view '. $type . ' content');
  }