Use llvm version of libcxxabi instead of patched mirror

[jmagman]

Bitcode has been removed from the engine flutter/flutter#107884

Revert #35873. Instead of using mirror at https://flutter.googlesource.com/third_party/libcxxabi/ with patch https://flutter.googlesource.com/third_party/libcxxabi/+/483f071ff4780a8884f32d97d2d262fbe9f1ae18, use llvm libcxxabi version.

See flutter/flutter#110140 for more details.

Once this merges https://flutter.googlesource.com/third_party/libcxxabi/ can probably be deleted. keep the fork around so older commits can be built.

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[flutter-dashboard]

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[Hixie]

how does this work? it's not in the allowed_hosts list.

[jmagman]

Hm, good question. llvm_git was introduced in #34720

@godofredoc any idea why this works when llvm.googlesource.com isn't in allowed_hosts?

engine/DEPS

Line 18 in 1eeb38c

'llvm_git': 'https://llvm.googlesource.com',

engine/DEPS

Lines 103 to 109 in 1eeb38c

	allowed_hosts = [
	'chromium.googlesource.com',
	'flutter.googlesource.com',
	'fuchsia.googlesource.com',
	'github.com',
	'skia.googlesource.com',
	]

I believe this logic is in https://chromium.googlesource.com/chromium/tools/depot_tools.git/+/refs/heads/main/gclient.py#931

[jmagman]

It looks like this is only validated during gclient verify, and it seems we aren't running that in CI. The infra team has been informed about this and I filed flutter/flutter#113052.

In the meantime this PR is no worse than what's already on master since libcxx is also using llvm_git, so I don't think we should block this PR on fixing that.

engine/DEPS

Lines 126 to 127 in 966f249

	'src/third_party/libcxx':
	Var('llvm_git') + '/llvm-project/libcxx' + '@' + '44079a4cc04cdeffb9cfe8067bfb3c276fb2bab0',

[Hixie]

test-exempt: rolling dependencies

[chinmaygarde]

Once this merges https://flutter.googlesource.com/third_party/libcxxabi/ can probably be deleted.

Please don't delete it as it makes building older commits impossible. Perhaps just a commit removing all files and placing a tombstone would be fine.

[jmagman]

Please don't delete it as it makes building older commits impossible.

Good point.

[auto-submit]

auto label is removed for flutter/engine, pr: 36634, due to - The status or check suite Linux License has failed. Please fix the issues identified (or deflake) before re-applying this label.

[jmagman]

cc @jason-simmons