ppb_file_ref: use raw file descriptor and specify file ref type
impl ppb_file_io_open (file_ref with handle case)
update ppb_url_response_info_get_body_as_file_ref status
impl ppb_file_io_request_os_file_handle
guess right return value for ppb_file_io_request_os_file_handle
ppb_file_io: close fd on destroy
ppb_url_loader: use redirect url from NPP_URLRedirectNotify