The build where the failure started is https://build.chromium.org/p/chromium.gpu.fyi/builders/Mac%20Pro%20Debug%20%28AMD%29/builds/9246 and the tests failing are:

gpu_tests.pixel_integration_test.PixelIntegrationTest.Pixel_ScissorTestWithPreserveDrawingBuffer
gpu_tests.pixel_integration_test.PixelIntegrationTest.Pixel_WebGLGreenTriangle_AA_NoAlpha
gpu_tests.webgl_conformance_integration_test.WebGLConformanceIntegrationTest.WebglConformance_conformance_context_context_attributes_alpha_depth_stencil_antialias
gpu_tests.webgl_conformance_integration_test.WebGLConformanceIntegrationTest.WebglConformance_conformance_context_context_size_change

For pixel tests, the failure is a mismatch between the expected and result image.

Looking at the changelist, my first guess is https://chromium.googlesource.com/chromium/src/+/7770a5a2b049424d3fa28d3c574fa49d51a19b33.

chris, could you take a look and confirm if its not from this change. Thanks.