[css-layout-api] "translate a LayoutConstraintsOptions to internal constraints" algorithm should take child layout as an argument

[heycam]

https://drafts.css-houdini.org/css-layout-api/#translate-a-layoutconstraintsoptions-to-internal-constraints

The last step says "If the child layout is a layout API container, ..." but there is nothing to say what that child layout should be. It probably should be passed in as an argument from the "run a work queue" algorithm that calls it.