Summary:There are two issues:
1. When calling startObserving or getCurrentPosition for the first time, _locationManager is not initialized and the accuracy value set in options is lost.
2. When using the cached location _lastLocationEvent, current timestamp retrieved by CFAbsoluteTimeGetCurrent() is from 2001, but the timestamp of the location is from 1970. In addition, the comparison between _lastLocationEvent[@"coords"][@"accuracy"] and options.accuracy is incorrect. Less value indicates more accurate location.
Closes https://github.com/facebook/react-native/pull/6198
Differential Revision: D3023786
Pulled By: nicklockwood
fb-gh-sync-id: 869c0e34252470275bf99cf0e5861747247f1158
shipit-source-id: 869c0e34252470275bf99cf0e5861747247f1158
49b2805da2