Michel Dänzer authored Feb 18, 2016 and Michel Dänzer committed Mar 01, 2016

The following fix will use the refactored function.

The logic in the refactored function is slightly simplified, exploiting
the fact that this function is only ever called with a valid flip
pixmap.

v2: Assert that flip_pixmap is non-NULL instead of testing and bailing
    on NULL, preserve test for flip_window being non-NULL before calling
    present_set_tree_pixmap for it (Keith Packard)

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> (v1)
Reviewed-by: Keith Packard <keithp@keithp.com>