Code:
cd /usr/ports/www/chromium
make build-depends-list | gtr -s \/ "\n" | grep -v usr | grep -v ports | grep -v textproc {etc !! } | {etc !! } | grep -v "missing upstream pkgs == py-gobject3 for example" | xargs -J % pkg install %
...
Once I got pkg working, that code-template [ too complex for actual code] ... if one runs it okay, then can run "pkg install -y" to actually do the upgrades. Coded that first within the last 48 hours ... but note the 'gtr' command (coreutils) which I had to work upon previously to strip the paths from the result, in other one-liners.