1429264 - Handle "pending" payment items in the UI

Status: NEW

(Firefox :: WebPayments UI, enhancement, P3)

Description

[Matthew N. [:MattN]]

`PaymentItem`s have a `pending`[1] boolean flag:

> When set to true it means that the amount member is not final. This is commonly 
> used to show items such as shipping or tax amounts that depend upon selection of 
> shipping address or shipping option. User agents MAY indicate pending fields in 
> the user interface for the payment request.  

We should decide what/if we're going to do with `pending` `PaymentItem`s

[1] https://w3c.github.io/payment-request/#dom-paymentitem-pending

Comment 1

[Matthew N. [:MattN]]

Hi Jacqueline, what do you think we should do for these? We can check what Chrome and Edge do with this demo: https://googlechrome.github.io/samples/paymentrequest/dynamic-shipping/
The shipping initially starts as $0 and `pending = true` but then changes once an address is selected.

Comment 2

[Matthew N. [:MattN]]

There is discussion at https://github.com/w3c/payment-request/issues/571 about how Apple and Chrome on Android handle `pending`.

Comment 3

[Jacqueline Savory [:jsavory] UX]

I'm adding this one into the next round of the wireframes, so removing the ni