CC'ing more GPU folks including pixel wrangler enne. Note that we think the blame list is not correct.. parent_got_v8_revision changed between

https://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Debug%20%28New%20Intel%29/builds/1742
https://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Debug%20%28New%20Intel%29/builds/1741

But there are no v8 rolls listed in the blame list for 

https://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Debug%20%28New%20Intel%29/builds/1742

Note that this test is timing out, so we suspect a v8 performance regression that shows up in the slower Debug tests:

WebglConformance_conformance_glsl_misc_shader_with_non_reserved_words (gpu_tests.webgl_conformance_integration_test.WebGLConformanceIntegrationTest) ... 
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:204
    'webglTestHarness._finished', timeout_in_seconds=300)
  traced_function at third_party\catapult\common\py_trace_event\py_trace_event\trace_event_impl\decorators.py:52
    return func(*args, **kwargs)
  WaitForJavaScriptCondition at third_party\catapult\telemetry\telemetry\internal\actions\action_runner.py:242
    self._tab.WaitForJavaScriptExpression(condition, timeout_in_seconds)
  traced_function at third_party\catapult\common\py_trace_event\py_trace_event\trace_event_impl\decorators.py:52
    return func(*args, **kwargs)
  WaitForJavaScriptExpression at third_party\catapult\telemetry\telemetry\internal\browser\web_contents.py:142
    e.message + '\n' + debug_message)
TimeoutException: Timed out while waiting 300s for IsJavaScriptExpressionTrue.

Filed  issue 670440  for the buildbot issue.  Looking into this.

I can't come up with anything substantial that might be causing these timeouts.  Am trying a speculative revert in https://codereview.chromium.org/2548583003/

I see a time increase from 42m17s to 44m10s that's a 5% regression on https://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Debug%20%28New%20Intel%29/builds/1740/steps/webgl_conformance_tests vs https://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Debug%20%28New%20Intel%29/builds/1742/steps/webgl_conformance_tests .

Do we have any webgl benchmarks regressing in the same time?

This seems to have gone green in https://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Debug%20%28New%20Intel%29/builds/1765.

I don't see anything obvious in the build where it went green. There's a skia roll (nothing looks related), plus a test suppression for a different test by kbr@ in the range (seems unrelated, but maybe this one was collateral damage?)

Feel free to reopen if it reoccurs.

Looks like I've been wrong about https://codereview.chromium.org/2544503002 causing problems.
https://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Debug%20%28New%20Intel%29/builds/1758 is the first one to have it reverted, but it's broken because of  issue 670984 .
But, https://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Debug%20%28New%20Intel%29/builds/1763 and https://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Debug%20%28New%20Intel%29/builds/1764 (which also have the revert) fail in the same way as https://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Debug%20%28New%20Intel%29/builds/1742 did.

Comparing 1742 blamelist with 1765, I see there were some skia changes touching the same area: https://skia-review.googlesource.com/c/5353/, https://skia-review.googlesource.com/c/5544/. I don't know skia, so I can't say if this code runs during this test.

I will take care of reverting the v8 revert.

To double confirm that v8 CL was unrelated: https://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Debug%20%28New%20Intel%29/builds/1779 has v8 CL relanded, and doesn't fail WebglConformance_conformance_glsl_misc_shader_with_non_reserved_words.