core(fr): align base artifacts with legacy gather-runner

[patrickhulce]

Summary
Brings the base artifacts support in FR up to snuff with legacy gather runner.

Related Issues/PRs
ref #11313

[adamraine]

Will base artifacts be available in gatherers as dependencies, or can we just pass them in FRTransitionalContext separately?

[adamraine]

nit: use another concat here?

[adamraine]

👀

[patrickhulce]

Will base artifacts be available in gatherers as dependencies, or can we just pass them in FRTransitionalContext separately?

Great question, this does not yet enable base artifacts as dependencies. We can talk about how to accomplish that when the need arises (has it already come up for you?). URL is the biggest one I can think of, but that's already available on the phaseContext.

[adamraine]

We can talk about how to accomplish that when the need arises (has it already come up for you?)

Yes, I know script-elements uses HostFormFactor.

I think it would be easier to include base artifacts separately in the context, or include them as dependencies for all gatherers by default. Essentially I want to avoid writing:

/** @type {LH.Gatherer.FRTransitionalContext<'HostFormFactor'>} */
meta = {
	supportedModes = ['navigation'],
	dependencies: {HostFormFactor: HostFormFactor.symbol},
}

[patrickhulce]

I think it would be easier to include base artifacts separately in the context

I was really hoping to avoid this for the reason that it's not obvious when base artifacts are actually populated and if they're available at the time they would be needed for the dependency. Making artifact dependency relationships explicit is pretty nice FR result.

Essentially I want to avoid writing:

That would actually be my ideal approach 😄 HostFormFactor and HostUserAgent actually make a lot of sense as regular artifacts too... I think what we need is the concept of artifacts that are always collected by default but aren't "special", to solve this.

[adamraine]

For our current set of Gatherers, it looks like we only need to depend on HostFormFactor and Settings. Explicit dependencies probably make sense here since there are so few instances of us depending on base artifacts.