Summary:
Starting on iOS 13, a View Controller presented modally will have a "bottom sheet" style unless it's explicitly presented full screen.
Before this, modals on iOS were only being dismissed programatically by setting `visible={false}`. However, now that the dismissal can happen on the OS side, we need a callback to be able to update the state.
This PR reuses the `onRequestClose` prop already available for tvOS and Android, and makes it work on iOS for this use case.
Should fix https://github.com/facebook/react-native/issues/26892
## Changelog
[iOS] [Added] - Add support for onRequestClose prop to Modal on iOS 13+
Pull Request resolved: https://github.com/facebook/react-native/pull/27618
Test Plan:
I tested this using the RNTester app with the Modal example:
1. Select any presentation style other than the full screen ones
2. Tap Present and the modal is presented
3. Swipe down on the presented modal until dismissed
4. Tap Present again and a second modal should be presented

Differential Revision: D19235758
Pulled By: shergin
fbshipit-source-id: c0f1d946c77ce8d1baab209eaef7eb64697851df
Summary:
In codegen we generate structs that represents events. These structs are later dispatched by generated `EventEmitter`.
They had unpleasant naming, for example `SliderOnValueChangeStruct`. This diff changes the code generated so it becomes `SliderEventEmitter::OnValueChange`, this better expresses the relationship of the two classes.
Changelog: [Internal]
Motivation: Better express relationship between EventEmitter and classes that represent events.
Reviewed By: rickhanlonii, shergin
Differential Revision: D19373850
fbshipit-source-id: a5eea085013dbc119169e2b06ba9f9fe44c7fcd9
Summary: We need to check if `_eventEmitter` is not nullptr before each call on it.
Reviewed By: sammy-SC
Differential Revision: D17531070
fbshipit-source-id: e9b5608845c10c7c2ef38f43c8deb67dad10fb6f
Summary: The previous rename from RCT->RN prefix ended up causing some confusions on which prefix to use for which files and under what circumstances. To avoid further confusion before we're done with the re-architecture project, let's keep them as RCT.
Reviewed By: mdvacca
Differential Revision: D16705566
fbshipit-source-id: 395bff771c84e5ded6b2261a84c7549df1e6c5e5