Object utility methods

[mahesh-hegde]

JNI API provides few useful methods related to class and objects equality. It would be nice to have higher-level wrappers for them working on JObject subclasses.

• [ ] #1033

  • Alternative: obj.isInstanceOf(ClassName.type)
  • Implementation: use isInstanceOf from JNI.

• [ ] IsSameObject - should we overload == to call IsSameObject from JNI? (Different ref values can point to same object).

• [ ] Get class name

  • This is a bit complicated, first we get jclass and call some methods on it: https://stackoverflow.com/questions/9265457/class-name-from-jclass-in-jni
  • Alternatively we can rely on dart-lang/native#711 and include Class<T> type.