See https://bugzilla.gnome.org/show_bug.cgi?id=758641 Upstream report this to be fixed in 2.46.3 but we are still using 2.46.2 so may need a backport or version bump. The patch applies to all 2.46 versions up to 2.46.3, thanks :)
Created attachment 425768 [details, diff] gdbusproxy-memleak_fix.diff
*glib-2.46.2-r2 (28 Feb 2016) 28 Feb 2016; Pacho Ramos <pacho@gentoo.org> +files/glib-2.46.2-memleak.patch, +glib-2.46.2-r2.ebuild: Fix memory leak (#575018 by Rick Harris), skip more broken tests