Summary:
Added method which checks if value(methodId, fieldId, class ...) returned by JNI functions (getMethod, getField, getClass ...) is valid or not and throw exception if they are not valid
##Changelog:
[Internal][Yoga] Add defensive check for result returned after JNI calls
Reviewed By: astreet
Differential Revision: D18745718
fbshipit-source-id: 2af26eda15fbe7834e1c9b274deeed4f106274ab
Summary: Add ScopedLocalRef, ScopedGlobalRef and some common methods to be used later.
Reviewed By: amir-shalem
Differential Revision: D17711284
fbshipit-source-id: be43d5e246bc2406765057783be11854877c41f1