This was causing GC-related crashes on various websites, most
prominently on any site that contains embedded YouTube videos. The issue
can be reproduced by going to any YouTube video, using the _Share_
button below it and pasting the embed code into an empty HTML file and
loading it through localhost.
This is technically a regression from
89dbdd3411 in that the problem became
visible with that commit. However, there is nothing wrong with the
commit by itself. It just happens that `Origin::is_same_origin_domain()`
prior to that commit was completely bogus and would mistakenly return
true in almost all cases, so the cross-origin code paths were not
exercised.
I am uncertain how to make a automatic test case for this problem, given
the nature of it being GC- and cross-origin-related. So there is no
regression test included in this commit.
This reverts commit c14173f651. We
should only annotate the minimum number of symbols that external
consumers actually use, so I am starting from scratch to do that
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
