Added in r462964. I'll disable it for now.

https://build.chromium.org/p/chromium.gpu.fyi/builders/Android%20Release%20%28Nexus%205%29/builds/4966

  Traceback (most recent call last):
    File "/b/c/b/Android_Release__Nexus_5_/irgpYPz5/third_party/catapult/telemetry/telemetry/testing/serially_executed_browser_test_case.py", line 194, in <lambda>
      return lambda self: based_method(self, *args)
    File "/b/c/b/Android_Release__Nexus_5_/irgpYPz5/content/test/gpu/gpu_tests/gpu_integration_test.py", line 73, in _RunGpuTest
      self.RunActualGpuTest(url, *args)
    File "/b/c/b/Android_Release__Nexus_5_/irgpYPz5/content/test/gpu/gpu_tests/webgl_conformance_integration_test.py", line 203, in RunActualGpuTest
      getattr(self, test_name)(test_path, *args[1:])
    File "/b/c/b/Android_Release__Nexus_5_/irgpYPz5/content/test/gpu/gpu_tests/webgl_conformance_integration_test.py", line 217, in _RunConformanceTest
      self._CheckTestCompletion()
    File "/b/c/b/Android_Release__Nexus_5_/irgpYPz5/content/test/gpu/gpu_tests/webgl_conformance_integration_test.py", line 213, in _CheckTestCompletion
      self.fail(self._WebGLTestMessages(self.tab))
  AssertionError: should be 255,0,0,255
  at (0, 0) expected: 255,0,0,255 was 0,0,255,255
  FAIL should be 255,0,0,255
  at (0, 0) expected: 255,0,0,255 was 0,0,255,255
  should be 0,0,255,255
  at (128, 0) expected: 0,0,255,255 was 255,0,0,255
  FAIL should be 0,0,255,255
  at (128, 0) expected: 0,0,255,255 was 255,0,0,255
  should be 0,128,255,255
  at (192, 0) expected: 0,128,255,255 was 255,128,0,255
  FAIL should be 0,128,255,255
  at (192, 0) expected: 0,128,255,255 was 255,128,0,255
  should be 255,128,0,255
  at (256, 0) expected: 255,128,0,255 was 0,128,255,255
  FAIL should be 255,128,0,255
  at (256, 0) expected: 255,128,0,255 was 0,128,255,255