refactor(core): add input and output filtering for host directives

[crisbeto]

Adds the logic that will filter out unexposed inputs/outputs and apply the aliases that the author specified when writing the host directives.

[crisbeto]

I'm not a fan of having this return an array when it might not need to, but I couldn't find a better way of producing two results from findDirectiveDefMatches. Some of the considered alternatives:

• Having a separate function that is called inside resolveDirectives that produces the map. The problem with this is that we don't have a way of distinguishing which matches came from host directives versus selector matching.
• Create the definition map inside resolveDirectives and pass it into findDirectiveDefMatches. This would work, but we might produce the binding map and not use it.
• Inverting the selector matching logic. We decided against doing so here refactor(core): generate initial inputs from inputs map #47228 (review).
• Have findDirectiveDefMatches return something like DirectiveDef[] | {matches: DirectiveDef[], mappings: HostDirectiveDefinitionMap} | null. This should be viable, but I'm not sure about the perf implications of generating object literals instead of arrays.

[AndrewKushnir]

Just as an idea, we can pass an object as an accumulator into the findDirectiveDefMatches function, for example:

const accumulator = {matchedDefs: null, hostDirectiveDefs: null};
collectDirectiveDefMatches(accumulator, ...);

I think the current approach is fine too, we do have the assertFirstCreatePass at the very beginning of the function, so we guarantee to invoke the function only once per component (at creation time), so it should not affect the performance.

[crisbeto]

That was one of the approaches I was considering, but I decided against it because we'd be creating the object even if we don't need it. That being said, I feel like I've been microoptimizing a bit here.

[crisbeto]

I was struggling a bit with how to name this so I'm open to suggestions.

[crisbeto]

The feedback has been addressed.

[pkozlowski-opensource]

If I'm not mistaken, the inputs / outputs field is applicable to directives that don't have any host directives applied to them, right? If so, I find the name HostDirectiveBindingMap misleading here. It is more about input / output aliasing, right?

[crisbeto]

It does two things:

1. It acts as an allowlist for the inputs/outputs that are exposed.
2. It's used to remap the public name.

I was struggling with how to capture this in the name of the symbol so I went with something more generic like "binding".

[crisbeto]

I ended up squashing the commits so it's easier to rebase the changes from #47530.

[pkozlowski-opensource]

LGTM overall.

Personally I had a different design on my mind where the feature is patching setInput and more of the code goes into the feature itself. But this would mean substantial re-design / re-write.

[pkozlowski-opensource]

LGTM

Reviewed-for: size-tracking
Reviewed-for: fw-core

[AndrewKushnir]

This PR was merged into the repository by commit 76a8c68.

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