[webkit-dev] Request for position: Aligning high-resolution timer granularity to cross-origin isolated capability

[Yoav Weiss]

Hey folks,

We recently changed <https://github.com/w3c/hr-time/pull/93> the HR-time
spec <https://w3c.github.io/hr-time/> to better align its resolution
clamping with cross-origin isolated capability
<https://html.spec.whatwg.org/multipage/webappapis.html#concept-settings-object-cross-origin-isolated-capability>,
and now I'm interested in shipping this change in Chromium.
In practice that means that Chromium would be reducing its resolution in
non-isolated contexts (regardless of the platform's site-isolation status)
to 100 microseconds, and increasing it in cross-origin isolated contexts
(even in platforms without site-isolation, e.g. Android) to 5 microseconds.

As WebKit already clamps those timers to 1ms (AFAIK), I'd mostly like your
position on the latter. Would y'all be interested in increasing timer
granularity in contexts which have guarantees against pulling in
cross-origin resources without their opt-in?

I'd appreciate your thoughts on the matter.

Cheers :)
Yoav
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