chromium/components/test/data/payments/payment_request_iframe.html

<!DOCTYPE html>
<script>

/**
 * Sends a payment request with the basic-card method.
 */
function triggerPaymentRequest() {
  triggerPaymentRequestWithMethods([{supportedMethods: 'basic-card'}]);
}

/**
 * Sends a payment request with the given methods.
 * @param {sequence<PaymentMethodData>} methodData An array of payment method
 *        objects.
 */
function triggerPaymentRequestWithMethods(methodData) {
  new PaymentRequest(
      methodData,
      {total: {label: 'Tots',
               amount: {currency: 'USD', value: '1.00'}}}).show();
}
</script>