http://www.trustedreviews.com/software/news/2009/11/20/Google-Unveils-Chrome-OS/p1
The video seems to say no localised file storage and no hard-wired applications. Which means unless you have internet connection it's a paperweight. Mobile devices should have a stripped down OS, but that if correct is to far. Means when travelling if you are in a black spot you can't do anything.
I'm sure when they announced Chrome OS they used pictures stored on a USB key or SD card to upload the to the internet. So I'm sure you'll be able to store videos on those and watch them if the browser supports the codec.