Here's the Chrome issue https://code.google.com/p/chromium/issues/detail?id=143619

I think it should be an easy fix since Chrome OS already supports hidpi displays.

At least some work has been done recently:

https://codereview.chromium.org/27156003/

http://src.chromium.org/viewvc/chrome/trunk/src/ui/base/reso...

So maybe Chrome 33-34?