Summary:
changelog: [internal]
Fix Flow types for UIManager measure functions.
Host platform does not accept null value for reactTag parameter. It errors if null is passed. This moves error closer to developers as Flow can catch it.
Reviewed By: javache
Differential Revision: D41614452
fbshipit-source-id: 2216c195808b8a1aae58c7cb2fa15be8a073e222