Hi there,
I found this interesting article on the chromium project website about the touch-based screen reader, but it was written in 2014 and I imagine they've been some improvements since then.
What I found interesting was that it seems to incorporate many of the best iOS touch gestures, alongside android talkback gestures, and even the positional-based element so that you can change settings by touching a particular area of the screen and swiping your finger up and down.
I have tried reaching out to chromium OS to see if it still being developed but there's no response, you won't have any more information about this.