Texture compression unaligned

[castano]

Issue: gpuweb/gpuweb#2006

Add tests to support the proposed 'texture-compression-unaligned' feature. gpuweb/gpuweb#6312

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Requirements for PR author:

• All missing test coverage is tracked with "TODO" or .unimplemented().
• New helpers are /** documented */ and new helper files are found in helper_index.txt.
• Test behaves as expected in a WebGPU implementation. (If not passing, explain above.)
• Test have be tested with compatibility mode validation enabled and behave as expected. (If not passing, explain above.)

Requirements for reviewer sign-off:

• Tests are properly located.
• Test descriptions are accurate and complete.
• Tests provide complete coverage (including validation control cases). Missing coverage MUST be covered by TODOs.
• Tests avoid over-parameterization (see case count report).

When landing this PR, be sure to make any necessary issue status updates.

[github-actions]

Results for build job (at d95bffb):

-webgpu:api,operation,adapter,requestDevice:features,known:* - 24 cases, 24 subcases (~1/case)
+webgpu:api,operation,adapter,requestDevice:features,known:* - 25 cases, 25 subcases (~1/case)
+webgpu:api,operation,command_buffer,copyTextureToTexture:color_textures,compressed,unaligned,non_array:* - 94 cases, 1974 subcases (~21/case)
+webgpu:api,operation,command_buffer,image_copy:compressed_textures,unaligned_mip_level_0:* - 156 cases, 780 subcases (~5/case)
+webgpu:api,validation,capability_checks,features,texture_compression_unaligned:createTexture,unaligned_size:* - 416 cases, 416 subcases (~1/case)
-TOTAL: 283186 cases, 2326094 subcases
+TOTAL: 283853 cases, 2329265 subcases

[Kangz]

I added experimental support for the extension in Chromium that you can try with --enable-unsafe-webgpu. It should appear in a Chromium Canary today or tomorrow (see when releases are listed here)

[castano]

I added experimental support for the extension in Chromium that you can try with --enable-unsafe-webgpu. It should appear in a Chromium Canary today or tomorrow (see when releases are listed here)

Thanks @Kangz! I tried with --enable-unsafe-webgpu on Chrome Canary 152.0.7939.2 and still don't see the feature exposed. Is this only exposed in Chromium? Are there any other flags that I may be missing?

[Kangz]

My bad, I thought the Chromium change trivial so I didn't check and I missed something. With that CL I can see the feature exposed locally (on mac M1) with --enable-unsafe-webgpu. So on Monday it should be in Canary.

[Kangz]

And I can't land that last CL because the existing tests will enable texture-compression-unaligned and fail. We should land this PR and follow up with completing tests afterwards. I checked earlier that the test pass with dawn.node. @kainino0x PTAL!