Avoid crashing on null user_data
Avoid crashing on null user_data

GNOME/at-spi2-atk,GNOME/at-spi2-core,gloob/gloob-s-at-spi2-core,Distrotech/at-spi2-atk,Distrotech/at-spi2-atk,gloob/gloob-s-at-spi2-core,GNOME/at-spi2-core,gloob/gloob-s-at-spi2-core,GNOME/at-spi2-core