I believe this is an error in the UI Events spec, and it should be
updated to match the HTML spec (which uses WindowProxy everywhere).
This fixes a bunch of issues already covered by existing WPT tests.
Spec bug: https://github.com/w3c/uievents/issues/388
Note that WebKit has been using WindowProxy instead of Window in
UI Events IDL since 2018:
816158b4aa
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
The main motivation behind this is to remove JS specifics of the Realm
from the implementation of the Heap.
As a side effect of this change, this is a bit nicer to read than the
previous approach, and in my opinion, also makes it a little more clear
that this method is specific to a JavaScript Realm.
