Fixed black screens (such as resuming app, opening app switcher in app, pulling down notification centre in app) and added Zephyr compatibility. Show and hide chat heads in response to more events (app switcher, device lock). Use the home button to dismiss chat head popups outside the Facebook app.
Revert "Fixed black screens (such as resuming app, opening app switcher in app, pulling down notification centre in app) and added Zephyr compatibility. Show and hide chat heads in response to more events (app switcher, device lock). Use the home button to dismiss chat head popups outside the Facebook app."

This reverts commit b76095417a65b370d92628546141d94d75c6c8f2.
Revert "Revert "Fixed black screens (such as resuming app, opening app switcher in app, pulling down notification centre in app) and added Zephyr compatibility. Show and hide chat heads in response to more events (app switcher, device lock). Use the home button to dismiss chat head popups outside the Facebook app.""

This reverts commit 22835765328d442c0d1b082c1681e838537c4fb3.