[PerformanceControlOfEmbeddedContent] Consider tooling support

[lflores-ms]

Loose transcript from BlinkOn talk feedback: 24:04

We do have certain attribution by origin in, say, Performance Panel and Network [...], by showing an accounting consistent with the way you're going to enforce it, it may help people to work on performance wihout any privacy issues there.

We actually need both [RUM and tooling] because a lot of problems would reproduce in lab conditions and [...] you can work on those problems proactively rather than getting things not rendering because of the intervention.