How do you put the blue dot on pinned Chrome tabs?

Certain google sites such开发者_如何转开发 as GMail, Google Voice, and others show a little blue dot when they update in the background (when the window doesn't have focus). This is definitely done through a JavaScript API. I've seen at least one other website (imo.im) do it as well.

How do you make this happen in JavaScript?

If you aren't entirely sure what I'm talking about, here is an image:

Apparently tabs flash automatically when you change the title, this does not work for pinned tabs however.

EDIT

Oh wait, it does work for pinned tabs, but not apps.

Source