Splitting this off https://bugs.chromium.org/p/chromium/issues/detail?id=900934: This test regressed 30-80%:
https://chromeperf.appspot.com/report?sid=c372fba2b849cc999b71624479e488b419270b1a3bc1aa25b4933e690bb06804&rev=604137

This is almost certainly:
EnableGpuRasterizationViewportRestriction bot config
https://chromium.googlesource.com/chromium/src/+/924edd7aee62613bf0d3f51b4c4d00e63f5c104e

@Eric, I think this is likely wontfix.