M65 Stable promotion is coming VERY soon. Your bug is labelled as Stable ReleaseBlock, pls make sure to land the fix and request a merge  into the release branch ASAP. Thank you.

We do have WebGL perf tests. However, it's next to impossible to evaluate all graphics perf. That's why WebGL working group never blessed a performance test suite, only a conformance one.

Also, this regression is specific to a group of Intel GPUs on Mac. I am not sure our how our perf waterfalls hardware coverage is.

I would suggest mark this as Won't Fix. Definitely not a release blocker for M65.

Oops, hit enter too soon.

Yes, I'm sorry but after discussion with zmo@ we think that this particular test is overly specific and not worth adding to the smoothness.tough_webgl_cases performance test, which is the only place where it could reasonably be added.

We are going to look at the tough_webgl_cases page set again and try to expand it for WebGL 2.0 cases, as well as expand the testing matrix. (alpha true/false; premultipliedAlpha true/false; preserveDrawingBuffer true/false; etc.)