Summary:
This diff refactors JNI methods used by the Binding.cpp class in order to use ReadableMap instead of ReadableNativeMap
This will be helpful to provide a different implementation of ReadableMap from C++
Reviewed By: shergin
Differential Revision: D14077762
fbshipit-source-id: 595b0c2d3a2d6070112257b65c1141a8af36f0e1