Started in https://build.chromium.org/p/chromium.gpu.fyi/builders/Linux%20Release%20%28ATI%29/builds/49431

Also failed in
https://build.chromium.org/p/chromium.gpu.fyi/builders/Linux%20Release%20%28ATI%29/builds/49434
https://build.chromium.org/p/chromium.gpu.fyi/builders/Linux%20Release%20%28ATI%29/builds/49439
https://build.chromium.org/p/chromium.gpu.fyi/builders/Linux%20Release%20%28ATI%29/builds/49441

The only CL in WebGL / ANGLE area I see is https://chromium-review.googlesource.com/#/c/399682/, though I have no idea if it's related.
Since it's flaky it might have been caused by something before that.

Log says:

WebglConformance_conformance2_buffers_uniform_buffers (gpu_tests.webgl_conformance_integration_test.WebGLConformanceIntegrationTest) ... [21132:21132:1021/205203:INFO:CONSOLE(172)] "WebGL: INVALID_OPERATION: bindBuffer: attempt to bind a deleted buffer", source: http://127.0.0.1:49067/third_party/webgl/src/sdk/tests/conformance2/buffers/uniform-buffers.html?webglVersion=2 (172)
[21132:21132:1021/205203:INFO:CONSOLE(11)] "Uniform offsets are not well aligned", source:  (11)
[21132:21132:1021/205203:INFO:CONSOLE(11)] "*** Error compiling FRAGMENT_SHADER '[object WebGLShader]':ERROR: 0:13: 'UBOGreen' : redefinition interface block member name
", source:  (11)
[21132:21132:1021/205203:INFO:CONSOLE(11)] "Error in compiling shader", source:  (11)
[21132:21132:1021/205203:INFO:CONSOLE(11)] "FAIL Uniform offsets are not well aligned", source:  (11)
[21132:21132:1021/205203:INFO:CONSOLE(11)] "Uniform offsets are not well aligned", source:  (11)
[21132:21132:1021/205203:INFO:CONSOLE(11)] "FAIL Uniform offsets are not well aligned", source:  (11)
[21132:21132:1021/205203:INFO:CONSOLE(11)] "Uniform offsets are not well aligned", source:  (11)
[21132:21132:1021/205203:INFO:CONSOLE(11)] "FAIL Uniform offsets are not well aligned", source:  (11)

Traceback (most recent call last):
  _RunGpuTest at content/test/gpu/gpu_tests/gpu_integration_test.py:78
    self.RunActualGpuTest(url, *args)
  RunActualGpuTest at content/test/gpu/gpu_tests/webgl_conformance_integration_test.py:196
    getattr(self, test_name)(test_path, *args[1:])
  _RunConformanceTest at content/test/gpu/gpu_tests/webgl_conformance_integration_test.py:210
    self._CheckTestCompletion()
  _CheckTestCompletion at content/test/gpu/gpu_tests/webgl_conformance_integration_test.py:206
    self.fail(self._WebGLTestMessages(self.tab))
  fail at /usr/lib/python2.7/unittest/case.py:412
    raise self.failureException(msg)
AssertionError: Uniform offsets are not well aligned
*** Error compiling FRAGMENT_SHADER '[object WebGLShader]':ERROR: 0:13: 'UBOGreen' : redefinition interface block member name

Error in compiling shader
FAIL Uniform offsets are not well aligned
Uniform offsets are not well aligned
FAIL Uniform offsets are not well aligned
Uniform offsets are not well aligned
FAIL Uniform offsets are not well aligned

Locals:
  msg : u"Uniform offsets are not well aligned\n*** Error compiling FRAGMENT_SHADER '[object WebGLShader]':ERROR: 0:13: 'UBOGreen' : redefinition interface block member name\n\x00\nError in compiling shader\nFAIL Uniform offsets are not well aligned\nUniform offsets are not well aligned\nFAIL Uniform offsets are not well aligned\nUniform offsets are not well aligned\nFAIL Uniform offsets are not well aligned\n"