Comment 7 for bug 867850

FWIW, I added a few more debug symbols and now have:
http://m8y.org/tmp/gnome-shell-crashes/

#0 0x00007fd53d2560a8 in g_slice_alloc () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1 0x00007fd5387cbd2a in pango_layout_get_iter () from /usr/lib/x86_64-linux-gnu/libpango-1.0.so.0
#2 0x00007fd536065a11 in cogl_pango_ensure_glyph_cache_for_layout (layout=0x2b0ba10) at cogl-pango-render.c:619
#3 0x00007fd53e3694e8 in clutter_text_create_layout (text=0x0, allocation_width=-1, allocation_height=1.86805797e-35) at ./clutter-text.c:785
#4 0x00007fd53e3699ce in clutter_text_get_preferred_width (self=<optimized out>, for_height=<optimized out>, min_width_p=0x7fffd14a7bc8, natural_width_p=0x7fffd14a7bcc) at ./clutter-text.c:2279
#5 0x00007fd53e2fe459 in clutter_actor_get_preferred_width (self=0x3e53000, for_height=-1, min_width_p=0x7fffd14a7c58, natural_width_p=0x7fffd14a7c5c) at ./clutter-actor.c:5948
#6 0x00007fd53f0e5da8 in ?? () from /usr/lib/gnome-shell/libgnome-shell.so
#7 0x00007fd53e2fe459 in clutter_actor_get_preferred_width (self=0x3e73140, for_height=-1, min_width_p=0x7fffd14a7e00, natural_width_p=0x7fffd14a7e08) at ./clutter-actor.c:5948