These are used by v8_wrapper/heap_test_utilities.* in Blink.
See crrev.com/c/2787126 for usage.

Bug: chromium:1056170
Change-Id: I329b1823f2ac21181a3536577ed72bee3d591347
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2786842
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73805}

This is a reland of eb453679

Original change's description:
> cppgc: Rework testing GC infrastructure
>
> Instead of moving the stand-alone logic to the base heap, allows
> specific heaps to override their stand-alone GC behavior. This allows
> CppHeap to reuse the unified heap bottlenecks and visitors for
> testing. This works as long as any v8 references are empty as there is
> no Isolate attached to the heap in this case.
>
> - Reverts parts of https://crrev.com/c/2716291
> - Relands parts of https://crrev.com/c/2718146
>
> In addition, add tests covering v8::CppHeap and cppgc::Heap.
>
> Bug: chromium:1056170
> Change-Id: I47dc88c7f0e4961a1aadd60da9b05bff4dcfb27a
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2718612
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Omer Katz <omerkatz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73077}

Bug: chromium:1056170
Change-Id: I415c837a7cf275c636172485dc4101c237a7d76b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2723253
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Omer Katz <omerkatz@chromium.org>
Auto-Submit: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73081}

This reverts commit eb453679.

Reason for revert: Breaks MSAN: https://ci.chromium.org/p/v8/builders/ci/V8%20Linux%20-%20arm64%20-%20sim%20-%20MSAN/37053

Original change's description:
> cppgc: Rework testing GC infrastructure
>
> Instead of moving the stand-alone logic to the base heap, allows
> specific heaps to override their stand-alone GC behavior. This allows
> CppHeap to reuse the unified heap bottlenecks and visitors for
> testing. This works as long as any v8 references are empty as there is
> no Isolate attached to the heap in this case.
>
> - Reverts parts of https://crrev.com/c/2716291
> - Relands parts of https://crrev.com/c/2718146
>
> In addition, add tests covering v8::CppHeap and cppgc::Heap.
>
> Bug: chromium:1056170
> Change-Id: I47dc88c7f0e4961a1aadd60da9b05bff4dcfb27a
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2718612
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Omer Katz <omerkatz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73077}

Bug: chromium:1056170
Change-Id: Ieda44c07d08f837a6632f96b8db6d5bec87dd521
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2723216
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Francis McCabe <fgm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73078}

Instead of moving the stand-alone logic to the base heap, allows
specific heaps to override their stand-alone GC behavior. This allows
CppHeap to reuse the unified heap bottlenecks and visitors for
testing. This works as long as any v8 references are empty as there is
no Isolate attached to the heap in this case.

- Reverts parts of https://crrev.com/c/2716291
- Relands parts of https://crrev.com/c/2718146

In addition, add tests covering v8::CppHeap and cppgc::Heap.

Bug: chromium:1056170
Change-Id: I47dc88c7f0e4961a1aadd60da9b05bff4dcfb27a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2718612
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73077}

This reverts commit ea818f07.

Reason for revert: Test failure in Linux64 UBSan https://ci.chromium.org/ui/p/v8/builders/ci/V8%20Linux64%20UBSan/15251/overview

Original change's description:
> cppgc: Fix testing APIs that enable garbage collection
>
> The APIs require that the CppHeap is moved into a permanently detached
> state that moves the heap out of a no-gc scope.
>
> Bug: chromium:1056170
> Change-Id: I1fc08451b3fdfaa4cfe58e6a1ddbe5dbed7efe5c
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2718146
> Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
> Reviewed-by: Omer Katz <omerkatz@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#73025}

Bug: chromium:1056170
Change-Id: Id00cb18274cbe7d255e7e95bd9e8e4dbc4b0c6e7
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2718658
Auto-Submit: Zhi An Ng <zhin@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Commit-Queue: Francis McCabe <fgm@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73029}

The APIs require that the CppHeap is moved into a permanently detached
state that moves the heap out of a no-gc scope.

Bug: chromium:1056170
Change-Id: I1fc08451b3fdfaa4cfe58e6a1ddbe5dbed7efe5c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2718146
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73025}

Bug: chromium:1056170
Change-Id: Ib2b2788c7d59f873583e26a0716bacbf16766c93
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2716291Reviewed-by: Omer Katz <omerkatz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73010}

cppgc/testing.h is already part of a testonly gn target which only can
be included from other test targets. This prevents any production
target to depend on cppgc/testing.h.

Bug: chromium:1056170
Change-Id: I51f6c47ffac2a05c8c63d7b4663c456a64fe75b4
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2689196Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72670}

Adds testing API that can only be used after enabling it on a heap.
The call that enables testing is only provided via v8_for_testing or
cppgc_for_testing build targets which protects against misusing from
production code.

Change-Id: I24a8f5543a2bb479481384e2c555d231383e5d12
Bug: chromium:1056170
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2667513Reviewed-by: Hannes Payer <hpayer@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Omer Katz <omerkatz@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72503}