Implementation class that handles Safari rendering issues.

class CaptionPanelImplSafari extends CaptionPanelImpl {

 void setSafeCaption(dart_html.FieldSetElement fieldset, dart_html.Element legend, SafeHtml caption) {
   setCaption(fieldset, legend, caption.asString(), true);
 }

 void setCaption(dart_html.FieldSetElement fieldset, dart_html.Element legend, String caption, [bool asHtml = true]) {
   fieldset.style.visibility = "hidden";
   super.setCaption(fieldset, legend, caption, asHtml);
   Scheduler.get().scheduleDeferred(new _CaptionPanelImplSafariScheduledCommand(fieldset));
 }
}