According to a report from David Ruddock of Android Police, Google is working to bring official Steam support to Chrome OS, something that would make Valve's PC game market the first of its kind on Google's platform. Ruddock spoke to Kan Liu, Director of Product Management for Chrome OS, where Liu confirmed the upcoming feature.
Liu did not confirm that Google is actually working with Valve on this, but he did talk about the elephant in the room, which is that Chrome OS hardware really isn't meant for gaming. Most people probably assumed that the answer for gaming on Chrome OS would be streaming with something like Google Stadia, as that doesn't require local resources.
There are some Chromebooks that can handle light gaming, such as HP's Chromebook x360 14, which has proper Intel Core processors. Liu says that more powerful Chromebooks are on the way, specifically those with AMD chips. Unfortunately, he wouldn't confirm anything with Nvidia graphics.
Right now, you can already run Steam on a Chromebook using the Linux app layer; however, it doesn't do very well. This would bring official support to the platform from Google, and presumably, that would be better.