Just sharing a thought since you will be working on this: what I don't like about this approach (and also didn't liked about the way `--install` and friends were implemented) is that we do a lot of initialization work to then figure out that we should not load a Browser Process at all. I'm giving some more thought on how to organize this (and XWalkBrowserMainParts) in a better way.

By "this approach" I mean: decide in PreMainMessageLoopRun() that we should not run the main loop.