Obligatory "Are you sure you want to do that?" and insert anti-command-line-flag rant here
That said,
content/public/common/content_switches.*
chrome/common/chrome_switches.*
Then just check the switches.
Of course, if you're also looking for something that can be controlled via policy, you'll want to add a pref, then also consider wiring up the command-line flag to the pref via chrome/browser/prefs/command_line_pref_store.*
And while you're at it wiring up a command-line pref, you should also consider adding an enterprise policy if appropriate, chrome/app/policy/policy_templates.json