Add CSD to border modes

This replaces view.using_csd with a new border mode: B_CSD. This also
removes sway_xdg_shell{_v6}_view.deco_mode and
view->has_client_side_decorations as we can now get these from the
border.

You can use `border toggle` to cycle through the modes including CSD, or
use `border csd` to set it directly. The client must support the
xdg-decoration protocol, and the only client I know of that does is the
example in wlroots.

If the client switches from SSD to CSD without us expecting it (via the
server-decoration protocol), we stash the previous border type into
view.saved_border so we can restore it if the client returns to SSD. I
haven't found a way to test this though.

1 files changed, 19 insertions, 0 deletions

diff --git a/include/sway/xdg_decoration.h b/include/sway/xdg_decoration.h
new file mode 100644
index 00000000..46fb8d34
--- /dev/null
+++ b/include/sway/xdg_decoration.h
@@ -0,0 +1,19 @@
+#ifndef _SWAY_XDG_DECORATION_H
+#define _SWAY_XDG_DECORATION_H
+
+#include <wlr/types/wlr_xdg_decoration_v1.h>
+
+struct sway_xdg_decoration {
+        struct wlr_xdg_toplevel_decoration_v1 *wlr_xdg_decoration;
+        struct wl_list link;
+
+        struct sway_view *view;
+
+        struct wl_listener destroy;
+        struct wl_listener surface_commit;
+};
+
+struct sway_xdg_decoration *xdg_decoration_from_surface(
+        struct wlr_surface *surface);
+
+#endif