src/freon: Reset CTM/GAMMA properties before switching back to Chrome
src/freon: Reset CTM/GAMMA properties before switching back to Chrome

Avoid display artifacts. Fixes #3791.

dnschneid/crouton,dnschneid/crouton,dnschneid/crouton,dnschneid/crouton,dnschneid/crouton,dnschneid/crouton