[Impeller] playground upload to device private on macOS

[jonahwilliams]

Generally this is fine to do regardless of whether or not we're on UMA . However I never finished flutter/flutter#123468 so it will only work on metal.

I don't think we have a way to runtime check if metal, so I added an ifdef for macos. Im not sure if we have vulkan on macos tests on CI, so lets find out.

Fixes flutter/flutter#124428

[flutter-dashboard]

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[gaaclarke]

LGTM. Just a note that what you are doing here to copy the texture is probably something that happens elsewhere and/or is worth capturing for easy use elsewhere.

It would be nice to verify that this unblocks #40998.

[gaaclarke]

The comment doesn't seem to align with the #if. The if blocks a platform, the comment talks about backends.

[jonahwilliams]

we don't have an ifdef for metal as far as I know. Technically macOS is only metal, except that we can run vulkan locally so this change breaks that without a modification to this code.

We can also fix this by finishing the blit pass implementation and removing the check altogether.

[jonahwilliams]

Looks like this did break something, but hard to tell from CI logs.

[gaaclarke]

Close, we get a new error now:

[INFO:test_timeout_listener.cc(76)] Test timeout of 120 seconds per test case will be enforced.
2023-04-07 16:14:10.433 impeller_unittests[28742:155517] Metal API Validation Enabled
-[MTLDebugBlitCommandEncoder generateMipmapsForTexture:]:1109: failed assertion `Generate Mipmaps For Texture Validation
[tex mipmapLevelCount](1) must be > 1.
'
[ERROR:flutter/fml/backtrace.cc(108)] Caught signal SIGABRT during program execution.
Frame 0: 0x7ff80b0f40cb err
Frame 1: 0x7ff813c2e8a4 MTLGetEnvCase<>()
Frame 2: 0x7ff813c18c05 MTLReportFailure
Frame 3: 0x7ff813c11378 _MTLMessageContextEnd
Frame 4: 0x7ff80b99a281 -[MTLDebugBlitCommandEncoder generateMipmapsForTexture:]
Frame 5: 0x10482b753 impeller::TextureMTL::GenerateMipmap()
Frame 6: 0x104814bee impeller::BlitPassMTL::EncodeCommands()
Frame 7: 0x1048148b0 impeller::BlitPassMTL::EncodeCommands()
Frame 8: 0x103f289e0 impeller::Playground::CreateTextureForMapping()
Frame 9: 0x103f28c84 impeller::Playground::CreateTextureForFixture()
Frame 10: 0x103eebeb6 impeller::testing::EntityTest_FilterCoverageRespectsCropRect_Test::TestBody()
Frame 11: 0x1049cc2ac testing::Test::Run()
Frame 12: 0x1049cd265 testing::TestInfo::Run()
Frame 13: 0x1049cdf75 testing::TestSuite::Run()
Frame 14: 0x1049dcb0d testing::internal::UnitTestImpl::RunAllTests()
Frame 15: 0x1049dc574 testing::UnitTest::Run()
Frame 16: 0x104093f5e main
Frame 17: 0x11094a52e start

[gaaclarke]

Here's the run: https://ci.chromium.org/ui/p/flutter/builders/try/Mac%20Engine%20Drone/154281/overview

[jonahwilliams]

Need to fix this

[gaaclarke]

Oops looks like thats a different function making that fixture than CreateTextureForDecompressedImage

[jonahwilliams]

Had to fix enable_mipmapping. Hopefully we're just using that one function for all playground tests...