Seems like it broke during code refactors over the last year. I have no idea if it's actually being used these days. The only mention on bugzilla is bug 373985 from 11 years ago. In case it's not being used, I'll attach a patch that simply removes it.
Comment on attachment 8974824 [details] Bug 1460734 - Remove macro DEBUG_DOCSHELL_FOCUS. https://reviewboard.mozilla.org/r/243200/#review249034
Attachment #8974824 - Flags: review?(bzbarsky) → review+
Pushed by firstname.lastname@example.org: https://hg.mozilla.org/integration/autoland/rev/b869cf66d81a Remove macro DEBUG_DOCSHELL_FOCUS. r=bz
You need to log in before you can comment on or make changes to this bug.