When the screen resizes, we get a configure event for the composite overlay
window - don't pass that to MetaStackTracker, since the COW isn't in the
stack.
Fixes warning:
mutter-WARNING **: STACK_OP_RAISE_ABOVE: window 0x65 not in stack
Add a private hook for the test framework to get XSyncAlarmEvent events -
this will be used to implement XSyncCounter based synchronization
so that the test framework can deterministically wait until Mutter
has seen actions performed by an X11 client.
https://bugzilla.gnome.org/show_bug.cgi?id=736505
This is so we won't poke into the MetaDisplay, which is invalid memory,
and crash. This can sometimes work right now because GSlice might not
deallocate the object immediately, but it's still not a fun thing to do.
