protected static function getDiffRevMsgAndClass(Revision $rev, FlaggedRevision $srev = null)
 {
     $tier = FlaggedRevision::getRevQuality($rev->getId());
     if ($tier !== false) {
         $msg = $tier ? 'revreview-hist-quality' : 'revreview-hist-basic';
     } else {
         $msg = $srev && $rev->getTimestamp() > $srev->getRevTimestamp() ? 'revreview-hist-pending' : 'revreview-hist-draft';
     }
     $css = FlaggedRevsXML::getQualityColor($tier);
     return array($msg, $css);
 }