Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/25671
Moves the RN-specific `ReactFiberErrorDialog` implementation from React to RN for easier iteration. Also adds new unit tests.
This current change is additive, so we're compatible with the current React renderer which still uses `ExceptionsManager` and not the file added here. After the corresponding React update we can remove `ExceptionsManager` from the RN private interface entirely.
Reviewed By: cpojer
Differential Revision: D16278938
fbshipit-source-id: 0c2c0c3e65e524e079730ae3b0cc23e0c0bdc5fd
Moti Zilberman