Only require that the stencil masks are same as many effective bits set It seems reasonable to validate the equality between stencilWriteMask and stencilBackWriteMask only by comparing the effective bits. An existing dEQP test[1] and a WebGL test[2] also use the max size of stencil bits for checking the stencil mask values. [1] StencilWriteMaskSeparateTestCase (gles3/functional/ es3fIntegerStateQueryTests.cpp) [2] https://www.khronos.org/registry/webgl/sdk/tests/conformance/state/ gl-get-calls.html (Search for "minimumRequiredStencilMask ") Change-Id: I68cefbe8a9f69c5a9ebcb30027a05581e3024add Reviewed-on: https://chromium-review.googlesource.com/302703 Reviewed-by: Corentin Wallez <cwallez@chromium.org> Tested-by: Jinyoung Hur <hurims@gmail.com> Commit-Queue: Jinyoung Hur <hurims@gmail.com> Tryjob-Request: Jamie Madill <jmadill@chromium.org>