The framework tree is currently red on an Engine roll here #99459.

https://ci.chromium.org/ui/p/flutter/builders/prod/Mac_ios%20platform_views_scroll_perf_ios__timeline_summary/3818/overview

It looks like the main thread is crashing in a call to GrMtlIsAppInBackground().

The Engine roll contains a clang roll. I will revert the Engine roll, stop the Engine rollers, and then speculatively revert the clang rolls if the framework tree returns to green.