The problem is, that at least in my experience chrome never does that. Which is why I recently had only 5g "available" (not free), and it was all swap, because Chrome had been a degenerate example of resource mismanagement on all of my computers since it was first released. I have yet to see Chrome free memory in way other than murdering the render process myself or closing the tabs and hoping it wasn't a shared process one, at least on Linux.