By making use of the WEB_PLATFORM_OBJECT macro we can remove
the boilerplate of needing to add this override for every
serializable platform object so that we can check whether they
are exposed or not.
This way databases are allowed to be GC'ed when there are no open
connections to them.
As a side effect, databases are no longer kept alive for the duration of
a browsing session. This will be addressed once IndexedDB gets proper
on-disk persistence. For now, avoiding memory leaks is the better
trade-off.
With this change the number of live `Window` objects in GC graph
captured by `test-web -j 1 --dump-gc-graph` goes down from 50 to 25.
C++ will jovially select the implicit conversion operator, even if it's
complete bogus, such as for unknown-size types or non-destructible
types. Therefore, all such conversions (which incur a copy) must
(unfortunately) be explicit so that non-copyable types continue to work.
NOTE: We make an exception for trivially copyable types, since they
are, well, trivially copyable.
Co-authored-by: kleines Filmröllchen <filmroellchen@serenityos.org>
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
