code: private JSType getNativeWildcardType() {
      if (isAllType) {
        return registry.getNativeType(ALL_TYPE);
      } else if (isNativeUnknownType) {
        if (areAllUnknownsChecked) {
          return registry.getNativeType(CHECKED_UNKNOWN_TYPE);
        } else {
          return registry.getNativeType(UNKNOWN_TYPE);
        }
      }
      return null;
    }
docs: Returns ALL_TYPE, UNKNOWN_TYPE, or CHECKED_UNKNOWN_TYPE, as specified by the flags, or null