check for existing pixmap when showing a window so we don't create a new pixmap if we don't need to.
check for existing pixmap when showing a window so we don't create a
new pixmap if we don't need to.

Signed-off-by: Chris Michael <177aeddb9e34930a357ecd8dd2d21c80fe280c85@samsung.com>

FlorentRevest/Enlightenment,rvandegrift/e,tizenorg/platform.upstream.enlightenment,FlorentRevest/Enlightenment,tasn/enlightenment,tizenorg/platform.upstream.enlightenment,FlorentRevest/Enlightenment,rvandegrift/e,tasn/enlightenment,rvandegrift/e,tizenorg/platform.upstream.enlightenment,tasn/enlightenment