Adds step and document_state properties. Both will be required for
further navigables spec implementation.
Co-authored-by: Andreas Kling <kling@serenityos.org>
These will need to float around more than they're currently able to.
Put them on the GC heap to prepare for that.
Co-authored-by: Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
(And BrowsingContextGroup had to come along for the ride as well.)
This solves a number of nasty reference cycles between browsing
contexts, history items, and their documents.
