compositor: reorganize struct weston_buffer_viewport

Queueing in the Presentation extension requires splitting the viewport
state into buffer state and surface state. To conveniently allow
assigning only one, the other, or both, reorganize the
weston_buffer_viewport structure.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
6 files changed