Handling PaymentResponse.prototype.onpayerdetailchange events
Each button will bring up the Payment Request UI window.
When shown the payment sheet, use any details and hit pay.
When asked to retry the payment:
If you find a buggy test, please file a bug
and tag one of the owners.
Change payer's name to "pass".
Change payer's email to "firstname.lastname@example.org".
Change payer's phone to "+1-800-000-0000".