mozilla/fireplace — pull request #607 by chuckharmston (2014-08-22 16:34:37+00:00)
Title: Prevent swipe navigation if the user is interacting with a tray (bug 1057360).

r? @ngokevin @spasovski

This is a kind of awkward solution, but hammer always passes the `HTMLDocument` as the swipe event target, and this was the best alternative I could divine.