Add using_csd variable to transaction state

This fixes a race condition flicker when unfloating a view which uses
client side decorations.

When the view is floated it has using_csd = true, so the decorations are
not drawn. When unfloating it it changes to false, but this change
wasn't part of transactions so it could potentially render the
decorations around the view while it's waiting for the transaction to
apply.

include/sway/tree/container.h

@@ -83,6 +83,7 @@ struct sway_container_state {
 	bool border_bottom;
 	bool border_left;
 	bool border_right;
+	bool using_csd;
 
 	// Workspace properties
 	struct sway_container *ws_fullscreen;

sway/desktop/render.c

@@ -266,7 +266,7 @@ static void render_view(struct sway_output *output, pixman_region32_t *damage,
 		render_view_toplevels(view, output, damage, view->swayc->alpha);
 	}
 
-	if (view->using_csd) {
+	if (view->swayc->current.using_csd) {
 		return;
 	}
 
@@ -585,7 +585,7 @@ static void render_container_simple(struct sway_output *output,
 				marks_texture = view->marks_unfocused;
 			}
 
-			if (!view->using_csd) {
+			if (!view->swayc->current.using_csd) {
 				if (state->border == B_NORMAL) {
 					render_titlebar(output, damage, child, state->swayc_x,
 							state->swayc_y, state->swayc_width, colors,
@@ -777,7 +777,7 @@ static void render_floating_container(struct sway_output *soutput,
 			marks_texture = view->marks_unfocused;
 		}
 
-		if (!view->using_csd) {
+		if (!view->swayc->current.using_csd) {
 			if (con->current.border == B_NORMAL) {
 				render_titlebar(soutput, damage, con, con->current.swayc_x,
 						con->current.swayc_y, con->current.swayc_width, colors,

sway/desktop/transaction.c

@@ -107,6 +107,7 @@ static void copy_pending_state(struct sway_container *container,
 		state->border_left = view->border_left;
 		state->border_right = view->border_right;
 		state->border_bottom = view->border_bottom;
+		state->using_csd = view->using_csd;
 	} else if (container->type == C_WORKSPACE) {
 		state->ws_fullscreen = container->sway_workspace->fullscreen;
 		state->ws_floating = container->sway_workspace->floating;