stylecontext: Make font hack not crash
stylecontext: Make font hack not crash

It's a lot uglier now, but it shouldn't crash anymore.

We must update the font description for animations, but we can't free it
on query, because some paths call gtk_style_context_get_font() twice in
a row without stopping the use of the first call. So us just creating a
new font description all the time and unreffing the old one is not a
good idea. So we just mere the new one into the old one.

https://bugzilla.gnome.org/show_bug.cgi?id=691186

ebassi/gtk,davidt/gtk,ahodesuka/gtk,Lyude/gtk-,Distrotech/gtk2,jadahl/gtk,jessevdk/gtk,ahodesuka/gtk,Sidnioulz/SandboxGtk,chergert/gtk,ebassi/gtk,grubersjoe/adwaita,jigpu/gtk,bratsche/gtk-,davidgumberg/gtk,Distrotech/gtk2,jadahl/gtk,msteinert/gtk,Adamovskiy/gtk,chergert/gtk,jigpu/gtk,jigpu/gtk,msteinert/gtk,bratsche/gtk-,ahodesuka/gtk,Sidnioulz/SandboxGtk,bratsche/gtk-,alexlarsson/gtk,grubersjoe/adwaita,Adamovskiy/gtk,bratsche/gtk-,ebassi/gtk,ahodesuka/gtk,bratsche/gtk-,Sidnioulz/SandboxGtk,jadahl/gtk,davidgumberg/gtk,jadahl/gtk,bratsche/gtk-,jessevdk/gtk,alexlarsson/gtk,jadahl/gtk,jadahl/gtk,jigpu/gtk,davidgumberg/gtk,chergert/gtk,chergert/gtk,jessevdk/gtk,Adamovskiy/gtk,msteinert/gtk,Adamovskiy/gtk,jigpu/gtk,Adamovskiy/gtk,Adamovskiy/gtk,jigpu/gtk,jessevdk/gtk,grubersjoe/adwaita,chergert/gtk,ahodesuka/gtk,ahodesuka/gtk,Distrotech/gtk2,alexlarsson/gtk,davidgumberg/gtk,alexlarsson/gtk,Lyude/gtk-,Lyude/gtk-,jessevdk/gtk,ebassi/gtk,jigpu/gtk,Distrotech/gtk2,davidt/gtk,chergert/gtk,Distrotech/gtk2,grubersjoe/adwaita,Sidnioulz/SandboxGtk,alexlarsson/gtk,davidgumberg/gtk,jadahl/gtk,alexlarsson/gtk,msteinert/gtk,alexlarsson/gtk,chergert/gtk,Lyude/gtk-,ahodesuka/gtk,alexlarsson/gtk,ahodesuka/gtk,davidt/gtk,msteinert/gtk,jadahl/gtk,Sidnioulz/SandboxGtk,davidgumberg/gtk,Sidnioulz/SandboxGtk,Adamovskiy/gtk,davidt/gtk,davidt/gtk,grubersjoe/adwaita,davidgumberg/gtk,davidt/gtk,Lyude/gtk-,msteinert/gtk,Lyude/gtk-,Adamovskiy/gtk,Distrotech/gtk2,jessevdk/gtk,davidgumberg/gtk,ebassi/gtk,chergert/gtk,jessevdk/gtk,grubersjoe/adwaita,grubersjoe/adwaita,jigpu/gtk,Lyude/gtk-,grubersjoe/adwaita,Lyude/gtk-,ebassi/gtk