All, or at least most, Chrome/Chromium command line switches are listed on this page: http://peter.sh/experiments/chromium-command-line-switches/. It is generated from Chromium source and contains links back to the source.
You are probably looking for --always-authorize-plugins
:
Prevents Chrome from requiring authorization to run certain widely
installed but less commonly used plug-ins.
I have no idea what "certain widely installed" means, but that's the closest thing you have in command line switches. It's entirely possible that your problem is unsolvable because it's a security restriction.