Store the initial xwayland position explicitly in struct shell_surface.
New variables are needed, because e.g. saved_x, saved_y are the view
position, and to compute that we need the window geometry, which is not
available before the first commit, so it's not available at
Regression: kcachegrind (Qt 4, X11), the first menu invocation will
slightly misplace the menu if the window has not been manually moved.
Problem: geometry is not taken into account due to a race between XWM
drawing decorations and Xwayland committing the first buffer.
Use the same debugging guard as XWM.
v3: merged with "desktop-shell: debug set_position_from_xwayland"
Signed-off-by: Pekka Paalanen <email@example.com>
Reviewed-by: Quentin Glidic <firstname.lastname@example.org>
Reviewed-by: Daniel Stone <email@example.com>