xwayland: Set wl_surface input region

Some applications that use client side decorations usually set custom input shape in order to prevent drop shadows stealing pointer events from windows below. Currently, the only way to get it is to use some XFixes APIs.

On the other hand, plenty of wayland compositors use solely the wl_surface input region to decide what view can receive pointer input, which results in some pointer input issues around client side drop shadows because Xwayland doesn't set wl_surface.input_region.

See-also: https://bugs.kde.org/show_bug.cgi?id=448119 Signed-off-by: Vlad Zahorodnii vlad.zahorodnii@kde.org