All chromium browsers had this for a long time. The point is - nobody really provided a feature to have N views with different resolutions for the same source
Blisk, Sizzy have been around for a while and do exactly this. Plus I remember something (maybe Rocketmelt?) offering a similar feature waaay back.
We stand corrected then.
There's also Emmet Re:view, an open source Chrome extension (apparently not actively developed though, and I've never used it): https://github.com/emmetio/re-view