This allows us:
- dogfood browser contexts the way we want them to be used
- simplifies the dance around service workers / cookies setting up and tier down.
This roll includes:
- https://crrev.com/547982 - v8 roll that includes [fixed
Runtime.callFunctionOn](1637818671) method
The upstream fix makes it possible to run frame.waitFor* functions on
pages with strict CSP.
References #1229.