void requestQuota(int newQuotaInBytes, [StorageQuotaCallback quotaCallback(int grantedQuotaInBytes), StorageErrorCallback errorCallback(DomError error)])

Source 

void requestQuota(int newQuotaInBytes, [StorageQuotaCallback quotaCallback, StorageErrorCallback errorCallback]) {
  if (errorCallback != null) {
    _blink.BlinkDeprecatedStorageQuota.instance.requestQuota_Callback_3_(unwrap_jso(this), newQuotaInBytes, unwrap_jso((grantedQuotaInBytes) => quotaCallback(grantedQuotaInBytes)), unwrap_jso((error) => errorCallback(wrap_jso(error))));
    return;
  }
  if (quotaCallback != null) {
    _blink.BlinkDeprecatedStorageQuota.instance.requestQuota_Callback_2_(unwrap_jso(this), newQuotaInBytes, unwrap_jso((grantedQuotaInBytes) => quotaCallback(grantedQuotaInBytes)));
    return;
  }
  _blink.BlinkDeprecatedStorageQuota.instance.requestQuota_Callback_1_(unwrap_jso(this), newQuotaInBytes);
  return;
}