This removes some ambiguity about what the return value should be if
the index is out of range.
Previously, we would sometimes return a JS null, and other times a JS
undefined.
It will also let us fold together the checks for whether an index is a
supported property index, followed by getting the value just afterwards.
(cherry picked from commit c5c1a8fcc78af986e5dd1a1f0bef1223e458ed37)
We don't need this for any case, so just remove it to simplify handling
in PlatformObject.
(cherry picked from commit 081c92bf3dc66773887243718cf41011289ac55e)
We have two known PlatformObjects that need to implement some of the
behavior of LegacyPlatformObjects to date: Window, and HTMLFormElement.
To make this not require double (or virtual) inheritance of
PlatformObject, move the behavior of LegacyPlatformObject into
PlatformObject. The selection of LegacyPlatformObject behavior is done
with a new bitfield of feature flags instead of a dozen virtual
functions that return bool. This change simplifies every class involved
in the diff with the notable exception of Window, which now needs some
ugly const casts to implement named property access.
Ultimately, this API should probably be replaced with something that
updates a cache on relevant DOM mutations instead of regenerating
the list of property names again and again.
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. :^)
