Summary:
Changelog: [Internal]
This adds definition of `PerformanceEventTiming` interface, according to the W3C standard, so that [event timing](https://www.w3.org/TR/event-timing) data can be reported from native (the C++ part is in the next diff).
See here: https://www.w3.org/TR/event-timing/#performanceeventtiming
Reviewed By: christophpurrer
Differential Revision: D42279486
fbshipit-source-id: 0dfbcd6e5a08fc1b89651bd35b24fb4e731f8b05
Ruslan Shestopalyuk