webdriver-bidi should have an event for FedCM dialogs

[cbiesinger]

The FedCM spec defines a number of commands to interact with FedCM dialogs: https://fedidcg.github.io/FedCM/#automation

However, most/all of the getters would be better done instead using an event with webdriver bidi, similar to what the devtools protocol uses: https://chromedevtools.github.io/devtools-protocol/tot/FedCm/#event-dialogShown

So I am filing this to track such an addition.

[cbiesinger]

@bvandersloot-mozilla fyi

[foolip]

@cbiesinger would you prefer to add something to https://fedidcg.github.io/FedCM/#automation, or to define in WebDriver BiDi itself? We don't have any extensions to BiDi in other specs yet, but I think long term that's just as natural as different specs defining their own Web IDL, and not centralizing everything in a single spec.

[cbiesinger]

I think the former would probably be preferable, if webdriver-bidi provides such an extension mechanism?

[jgraham]

The intent is definitely to allow other specs to extend BiDi. At the moment the way extension points will work is somewhat unclear, but possibly you can go ahead without much explicit prose in BiDi to help you; basically you'd need to define a module with some CDDL that describes your commands / events / types and then do something like

Command //= FedCMCommand

to extend the top-level definitions.

Of course we currently lack the tooling to make this work nicely (e.g. by extracting the full CDDL definition from across multiple specs), but that doesn't seem like a blocker.

[OrKoN]

@cbiesinger here are two examples of BiDi extensions https://webbluetoothcg.github.io/web-bluetooth/#bluetooth-module and https://www.w3.org/TR/permissions/#automation-webdriver-bidi

[OrKoN]

The bluetooth one also includes events.