Revert "heap: Fix plugin bug for cppgc builds"

This reverts commit 67d165e9093678046a8b24e6b7c63cf3dcb4e8a4. The
reason: GarbageCollectedBase was removed in cppgc to make sure that
empty-base-optimization happens for GarbageCollected.

Original description:
> heap: Fix plugin bug for cppgc builds
>
> cppgc::GarbageCollected and cppgc::GarbageCollectedMixin inherit from
> cppgc::GarbageCollectedBase. The base class doesn't exist in blink. as a
> result, when checking the left most parent of GCed classes we find
> cppgc::GarbageCollectedBase and erroneously report errors.
> Since we should still distinguish cppgc::GarbageCollected from
> cppgc::GarbageCollectedMixin, the solution is to ignore the
> cppgc::GarbageCollectedBase and return the its subclass as the left most
> parent of the class.
>
> Bug: chromium:1056170
> Change-Id: I848daf98a8ef363a436dee2cf921d81309d5a02d
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2672008
> Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
> Commit-Queue: Omer Katz <omerkatz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#850110}

Bug: 1260797
Change-Id: Iad896bd8cc02002e29625d426e9093904fc9af95
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3259707
Commit-Queue: Anton Bikineev <bikineev@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#939281}
NOKEYCHECK=True
GitOrigin-RevId: 9986d154909954224470474721596fde7d852d39
4 files changed