Summary:
`Animated.parallel` among other functions expects the `start(callback)` function to be invoked with an `endState` object. Currently natively driven animations call the handler with `null`, this PR changes that to `{ finished: true }`.
**Test plan**
This should not throw any errors:
```js
Animated.parallel([
Animated.timing(
new Animated.Value(0),
{
toValue: 1,
useNativeDriver: true
}
),
Animated.timing(
new Animated.Value(0),
{
toValue: 1,
useNativeDriver: true
}
)
]).start();
```
Closes https://github.com/facebook/react-native/pull/8567
Differential Revision: D3517291
Pulled By: javache
fbshipit-source-id: 0056a5b4261546b061451c0b1b249718739086bc
cc816fbd82