Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/35526
[Changelog][Internal]
This closes the full loop according to the [technical design](https://fb.quip.com/MdqgAk1Eb2dV) of the WebPerf API implementation, with the main components and the working central data flow in place.
The next step is to add some buffering/throttling, as in this diff we just spawn an idle-priority task after every performance entry coming (even though they still naturally do come in batches, because they manage to accumulate before the task is executed).
Reviewed By: christophpurrer
Differential Revision: D41496082
fbshipit-source-id: 5fd4cf22e75806f7bc98d1d1b6691596ccadf8b9