Does not compile for iOS on Unity - GvrPermissionsRequester missing

[klauskobald]

I get these errors on build:
Assets/Scripts/Util/RequestPermission.cs(27,25): error CS0246: The type or namespace name `GvrPermissionsRequester' could not be found. Are you missing an assembly reference?

Am I missing something? Is there a library that has to be installed to somewhere before? I only downloaded this repo.