Summary:
Some of the flow types were incomplete. So, I referenced the code in `~/fbsource/xplat/js/react-native-github/ReactAndroid/src/main/java/com/facebook/react/views/textinput/` and in `~/fbsource/xplat/js/react-native-github/Libraries/Text/TextInput/` to make the flow types more specific.
I also fixed internal breakages. To avoid having to sprinkle `$FlowFixMe`s everywhere, I had to refactor some types, and some code.
Reviewed By: TheSavior
Differential Revision: D13121871
fbshipit-source-id: 9796aafc861544baf52d7ade823ab1be2d3f12d1
da0b139b56