This function changes the user and group owner of a file. It is the same of the shell command chown.
Pointer to a valid FileOperations class.
The file/dir name to work on
New user id for the file
New group id for the file
should return AFC_ERR_NO_ERROR
If chown fails, you may get AFC_FILEOPS_ERR_CHOWN, but only if you set that chown errors are blocking with afc_fileops_set_tag()
This function may or may not return an error value in case of real errors, depending on the settings you have made using afc_fileops_set_tag() or afc_fileops_set_tags()