There is API now for printers [1]. There is HP driver for example, that probably uses that [2]. And it seems that someone made up driver for Brother AIOs.

[1] https://developer.chrome.com/apps/printerProvider

[2] https://chrome.google.com/webstore/detail/hp-print-for-chrom...

[3] https://chrome.google.com/webstore/detail/wifi-printer-drive...