So will $logviewer->get_log_records()->XML_file(); just call both the functions or is there any other scenario I am failing to understand.

Perl calls get_log_records on $logviewer, and it calls XML_file on whatever object is returned by get_log_records. This maybe the same object as $logviewer, but without inspecting what get_log_records does, is something that cannot be answered. It's very well possible methods in different classes are being called.