Summary: see https://github.com/facebook/flipper/issues/450 If we want to control a custom SharedPreferences, we can create a Class as SharedPreferencesDescriptor's Subclass, override the getSharedPreferences() function to return a custom SharedPreferences instance. ## Changelog add getSharedPreferences() function in SharedPreferencesDescriptor Class Pull Request resolved: https://github.com/facebook/flipper/pull/571 Test Plan: No Reviewed By: jknoxville Differential Revision: D17738675 Pulled By: passy fbshipit-source-id: d227e7d6461194f7a01ae7b2ba53434dd71fc0d2