Security restrictions on various operating systems and OS configurations can cause
headless Chrome execution to fail. As a result, headless Chrome operations should
use a special directory for decapitated package operations. You can pass this
in as work_dir. If work_dir is NULL a .rdecapdata directory will be
created in your home directory and used for the data, crash dumps and utility
directories for Chrome operations.
tempdir() does not always meet these requirements (after testing on various
macOS 10.13 systems) as Chrome does some interesting attribute setting for
some of its file operations.
If you pass in a work_dir, it must be one that does not violate OS security
restrictions or headless Chrome will not function.