[Payment Request] log if `updateWith` is not called synchronously

[Devin Rousso]

According to <https://www.w3.org/TR/payment-request/#updatewith-method>:
> To prevent the user interface from blocking (and to reflect changes made by the end user through the UI), developers need to immediately call `updateWith()`.
AFAICT the spec doesn't specify what the user agent should do in the case that the developer doesn't immediately call `updateWith()`, but I think there should at least be a console message to help developers understand that this is expected (without expecting them to have to read the spec).

[Devin Rousso]

Created attachment 421557 [details]
Patch

[Andy Estes]

Comment on attachment 421557 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=421557&action=review

> Source/WebCore/Modules/paymentrequest/PaymentRequest.cpp:710
> +    scriptExecutionContext()->addConsoleMessage(JSC::MessageSource::PaymentRequest, JSC::MessageLevel::Error, makeString("updateWith() must be called synchronously when handling \""_s, event->type(), "\"."_s));

As we discussed, I think we should change "must" to "should".

[Devin Rousso]

Created attachment 421562 [details]
Patch

[Devin Rousso]

Created attachment 421608 [details]
Patch

[EWS]

Committed r273562: <https://commits.webkit.org/r273562>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 421608 [details].

[Radar WebKit Bug Importer]

<rdar://problem/74794561>