Summary:
This PR introduces a new helper function called `setAndForwardRef`. It is intended to help with moving components that depend on `NativeMethodsMixin` off of `createReactClass`.
It allows for classes that depend on having a ref to a native component to be able to also forward the native component ref to user code.
Usage is like this:
```js
class MyView extends React.Component {
_nativeRef = null;
_setNativeRef = setAndForwardRef({
getForwardedRef: () => this.props.forwardedRef,
setLocalRef: ref => {
this._nativeRef = ref;
},
});
render() {
return <View ref={this._setNativeRef} />;
}
}
const MyViewWithRef = React.forwardRef((props, ref) => (
<MyView {...props} forwardedRef={ref} />
));
module.exports = MyViewWithRef;
```
Pull Request resolved: https://github.com/facebook/react-native/pull/21823
Differential Revision: D10436673
Pulled By: TheSavior
fbshipit-source-id: 32e167bb3ea3234f08d5715168b0e61e4e035a7c
d6c8f189e7