Is it possible to write to a USB stick (or other external storage device) using a Chromium extension?

I'm trying to develop something similar to the Chromebook Recovery Utility (in the sense that it's an extension that can flash .bin files to an external storage device) but I'm not sure how to do it, or if it's even possible. I know WebUSB lets extensions such interface with microcontrollers, would that work in this case? Could you pretend a USB stick is a microcontroller then just write files to it? Would WebHID work as well?

Question by Jack Wagon on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.