DynamicSlowMPU:with three bigs

Build 4236 on doml/remove-fronts-banner-ads-switch
740px
Reviewing disabled
The baseline is shorter than the new snapshot (740x747 to 740x765).
Baseline History
Build 42360d4e4ec
Current build. There are unaccepted changes, so build 2474 is still the baseline.
Build 24617405ee1
Auto-accepted
Build 207681411e8
Accepted by Daniel Clifton.
Build 20551a01a5b
Accepted by Anna Beddow.
Commenting is disabled because there's a newer build on this branch