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.
Same thing for chrome - often people say "chrome eats your RAM" but it's just being as efficient as it can be - if your OS asks it to free ram, it will and 8GB of webpages can go down to 4GB at the expense of getting rid of cached "back" pages and other cached memory.