Summary:
After a fair bit of use, we have concluded that the `ItemComponent` mechanism is not worth the
hassle. Flow has trouble type checking it thoroughly, requiring an 'item' prop is annoying, and it
is very common to need to capture `this` anyway, e.g. for an `onPress` handler. A common pattern was
something like:
_renderItem = ({item}) => <MyItem foo={item.foo} onPress={() => this._onPress(item)} />};
...
ItemComponent={this._renderItem}
which wouldn't flow check the props and doesn't benefit from reusing components.
If we find some specific patterns that would benefit from the `ItemComponent` pattern, we can create
a new component that provides that API and wraps `FlatList` under the hood.
I'm going to do `SectionList` in a stacked diff.
Reviewed By: bvaughn
Differential Revision: D4625338
fbshipit-source-id: a4901f1c9d77e0115b0b8032b8c210f624e97ea3
2a1ab36257