protocol: Add wl_surface.offset

This is meant to address the issue where the call to 'wl_surface.attach'
is done by e.g. Vulkan, meaning applications cannot affect the values of
the offset passed as the x and y arguments.

The lack of ability to pass these is problematic when using the Vulkan
for e.g. drawing DND surfaces, as the buffer offset is used to implement
the drag icon hotspots.

Closes: wayland/wayland#148
Signed-off-by: Jonas Ådahl <jadahl@gmail.com>
Reviewed-by: Simon Ser <contact@emersion.fr>
3 jobs for wip/surface-offset in 59 seconds (queued for 5 seconds)
latest
Status Job ID Name Coverage
  Review
passed #11377560
check-commit

00:00:11

 
  Prep
passed #11377561
debian:buster@container-prep

00:00:25

 
  Build
passed #11377562
build-native

00:00:22