after landing of bug 378193 i still see this leak, which seems to be like a similar fix would do:
==16630== 27,616 (2,368 direct, 25,248 indirect) bytes in 8 blocks are definitely lost in loss record 205 of 218
==16630== at 0x4C278AE: malloc (vg_replace_malloc.c:207)
==16630== by 0x6DAF303: (within /usr/lib/libcairo.so.2.10800.8)
==16630== by 0x6DAF657: (within /usr/lib/libcairo.so.2.10800.8)
==16630== by 0x412776: _refresh_background (bubble.c:517)
==16630== by 0x41373E: bubble_recalc_size (bubble.c:3268)
==16630== by 0x41AFA9: stack_notify_handler (stack.c:645)
==16630== by 0x41A095: dbus_glib_marshal_stack_VOID__STRING_UINT_STRING_STRING_STRING_BOXED_BOXED_INT_POINTER (stack-glue.h:100)
==16630== by 0x52797EB: (within /usr/lib/libdbus-glib-1.so.2.1.0)
==16630== by 0x5279CA4: (within /usr/lib/libdbus-glib-1.so.2.1.0)
==16630== by 0x54AB61D: (within /lib/libdbus-1.so.3.4.0)
==16630== by 0x549F3DB: dbus_connection_dispatch (in /lib/libdbus-1.so.3.4.0)
==16630== by 0x5276B64: (within /usr/lib/libdbus-glib-1.so.2.1.0)
still High importance imo as its important to get a leak free notify-osd.