It's not possible to do a screencast on a ChromeBook or in Chrome with web apps

I have already stumbled over a huge drawback in my new Google experiment, my Google Journey where I try to only use web apps in Chrome and Google Services... There is no way to do a screencast where I record what's on my screen. There is no web app for it, so it's not possible to do on a ChromeBook or as in my case, Chrome Web Browser running on my 11-inch MacBook Air!

The only way doing it is by doing a Google Hangout On Air, and I don't want to do that, because that means that I am sending out my screen live on my YouTube channel. That's by no means an option for me. I need to edit the video before showing it to the public...

SO what to do? There is simply no way, so it is impossible for me to only use a ChromeBook or web apps in Chrome. At least until there will be a web app available for this. So I need to use a Mac app for that.

Sigh, my new Google experiment doesn't start so good.. But I will of course continue to explore the possibilities in my experiment.