Summary:
Cleans up the Flow types for React Native ViewConfig. After this diff, we will have two new canonical types:
- `ViewConfig` which is what we get from native and what is registered in the `ReactNativeViewConfigRegistry`.
- `PartialViewConfig` which is what we generate statically and augment at runtime before registering with the `ReactNativeViewConfigRegistry`.
Changelog:
[Internal]
Reviewed By: JoshuaGross
Differential Revision: D25075299
fbshipit-source-id: 4b53927b2db437b615447b711e83db355d0cfa55