With this change, we now have ~1200 CellAllocators across both LibJS and
LibWeb in a normal WebContent instance.
This gives us a minimum heap size of 4.7 MiB in the scenario where we
only have one cell allocated per type. Of course, in practice there will
be many more of each type, so the effective overhead is quite a bit
smaller than that in practice.
I left a few types unconverted to this mechanism because I got tired of
doing this. :^)
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 :^)
This Intrinsics object hangs off of a new HostDefined struct that takes
the place of EnvironmentSettingsObject as the true [[HostDefined]] slot
on JS::Realm objects created by LibWeb.
This gets the intrinsics off of the GlobalObject, Window, similar to the
previous refactor of LibJS to move the intrinsics into the Realm's
[[Intrinics]] internal slot.
A side effect of this change is that we cannot fully initialize a Window
object until the [[HostDefined]] slot has been installed into the realm,
which happens with the creation of the WindowEnvironmentSettingsObject.
As such, any Window usage that has not been funned through a WindowESO
will not have any cached Web prototyped or constructors, and will not
have Window APIs available to javascript code. Currently this seems
limited to usage of Window in the CSS parser, but a subsequent commit
will clean those up to take Realm as well. However, this commit compiles
so let's cut it off here :^).
