x11: Defer _NET_WM_FRAME_DRAWN update until frame usable by compositor

x11: Defer _NET_WM_FRAME_DRAWN update until frame usable by compositor

With the vendor provided Nvidia driver there is a small window of time
after drawing to a GL surface before the updates to that surface
can be used by the compositor.

Drawing is already coordinated with the compositor through the frame
synchronization protocol detailed here:

https://fishsoup.net/misc/wm-spec-synchronization.html

Unfortunately, at the moment, GdkX11Surface tells the compositor the
frame is ready immediately after drawing to the surface, not later,
when it's consumable by the compositor.

This commit defers announcing the frame as ready until it's consumable
by the compositor. It does this by listening for the X server to announce
damage events associated with the frame drawing.  It tries to find the
right damage event by waiting until fence placed at buffer swap time
signals.