Seen on Win10 FYI Release (NVIDIA):
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Win10%20FYI%20Release%20%28NVIDIA%29/1660

[103/136] gpu_tests.webgl_conformance_integration_test.WebGLConformanceIntegrationTest.WebglConformance_deqp_functional_gles3_occlusionquery_strict failed unexpectedly 25.8110s:
  
  Traceback (most recent call last):
    _RunGpuTest at content\test\gpu\gpu_tests\gpu_integration_test.py:132
      self.RunActualGpuTest(url, *args)
    RunActualGpuTest at content\test\gpu\gpu_tests\webgl_conformance_integration_test.py:185
      getattr(self, test_name)(test_path, *args[1:])
    _RunConformanceTest at content\test\gpu\gpu_tests\webgl_conformance_integration_test.py:199
      self._CheckTestCompletion()
    _CheckTestCompletion at content\test\gpu\gpu_tests\webgl_conformance_integration_test.py:195
      self.fail(self._WebGLTestMessages(self.tab))
    fail at .swarming_module\bin\Lib\unittest\case.py:410
      raise self.failureException(msg)
  AssertionError: occlusion_query.scissor_stencil_write_stencil_clear: Query result not available after 5.144 seconds.


Possible this is caused by a bug in GL context virtualization?

Most of the other webgl2_conformance_gl_passthrough_tests failures seen on this bot are random test timeouts. No real pattern to them.

Unless this shows up again it's not clear it's worth adding a Flaky suppression.