Summary:
By default we run the the JS display link, even if there are no modules listening. Given that most listeners will be lazily constructed, let's make it paused by default.
Since RCTTiming almost never unpauses due to some long-lived timers, implement a sleep timer that pauses the displaylink but uses an NSTimer to wake up in time.
Reviewed By: mhorowitz
Differential Revision: D3235044
fbshipit-source-id: 4a340fea552ada1bd8bc0d83b596a7df6f992387