SqlDatabase openDatabase(String name, String version, String displayName, int estimatedSize, [DatabaseCallback creationCallback(SqlDatabase database)])

Source 

SqlDatabase openDatabase(String name, String version, String displayName, int estimatedSize, [DatabaseCallback creationCallback]) {
  if (creationCallback != null) {
    return wrap_jso(_blink.BlinkWindow.instance.openDatabase_Callback_5_(unwrap_jso(this), name, version, displayName, estimatedSize, unwrap_jso((database) => creationCallback(wrap_jso(database)))));
  }
  return wrap_jso(_blink.BlinkWindow.instance.openDatabase_Callback_4_(unwrap_jso(this), name, version, displayName, estimatedSize));
}