We were relying on the XRandR events from the X server to update
the configuration, but we were calling meta_monitor_config_update_current()
immediately after, so the MonitorConfig would be updated with the
old configuration (and we would save that to disk!)
https://bugzilla.gnome.org/show_bug.cgi?id=705670
First disable CRTCs that should be off in the new configuration,
then resize the framebuffer, then enable the new CRTCs.
If we don't do that, and we're making the screen smaller, X complains
with a BadMatch.
https://bugzilla.gnome.org/show_bug.cgi?id=705670
Add "edid-file", if we have one (in the KMS case, where we can point
people to the right sysfs file), or "edid" with inline data.
These are needed by colord to build the default ICC profile for
uncalibrated displays.
https://bugzilla.gnome.org/show_bug.cgi?id=705670
Instead of keeping a forest of if backend else ..., use a subclass
and virtual functions to discriminate between XRandR and the
dummy backend (which lives in the parent class togheter with the
common code)
https://bugzilla.gnome.org/show_bug.cgi?id=705670