Polymer/core-overlay — pull request #3 by nevir (2014-06-13 21:15:31+00:00)
Title: Protect against infinite recursion in focusOverlay

Note that this doesn't fix the root cause; it just tries to be a bit more
safe against corrupt state. Another PR is on the way to fix that.

An easy way to repro the infinite recursion is to create multiple *opened*
overlays, and dismiss them at the same time (toasts).