was leaking an nsIPref thing for "efficiency" reasons (actually, the truth
is I was just lazy when I wrote the code, but dont tell my mom) The fix was
to register pref changed callbacks to avoid having to keep an nsIPref alive
and thus avoiding some memory leaks which were adding noise to the leak logs.
r=pavlov.
git-svn-id: svn://10.0.0.236/trunk@55170 18797224-902f-48f8-a5cc-f745e15eee43
119acf2584