Summary:
For a very long time, iOS has supported the `contentOffset` property but Android has not:
https://github.com/facebook/react-native/issues/6849
This property can be used, primarily, to autoscroll the ScrollView to a starting position when it is first rendered, to avoid "jumps" that occur by asynchronously scrolling to a start position.
Changelog: [Android][Changed] ScrollView now supports `contentOffset`
Reviewed By: mdvacca
Differential Revision: D21198236
fbshipit-source-id: 2b0773569ba42120cb1fcf0f3847ca98af2285e7