first failure:
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Mac%20FYI%20Retina%20Debug%20%28NVIDIA%29/2964

webgl_conformance_tests on NVIDIA GPU on Mac Retina on Mac-10.13.5 
Unexpected Failures:
* gpu_tests.webgl_conformance_integration_test.WebGLConformanceIntegrationTest.WebglConformance_conformance_uniforms_uniform_samplers_test

Looks like it is timing out.  A previous passing run needed 278 seconds.

TimeoutException: Timed out while waiting 300s for IsJavaScriptExpressionTrue.
Console output:

Locals:
  IsJavaScriptExpressionTrue : <function IsJavaScriptExpressionTrue at 0x113c0e488>
  condition                  : 'webglTestHarness._finished'
  context_id                 : None
  debug_message              : 'Console output:\n'
  e                          : TimeoutException('Timed out while waiting 300s for IsJavaScriptExpressionTrue.',)
  kwargs                     : {}
  timeout                    : 300