shell: Make input capture optional for curtains

desktop-shell's focus surfaces want to reuse this, but they don't want
to capture the input, instead allowing it to fall through.

Signed-off-by: Daniel Stone <daniels@collabora.com>

shared/shell-utils.c

@@ -173,8 +173,12 @@ weston_curtain_create(struct weston_compositor *compositor,
 	}
 
 	pixman_region32_fini(&surface->input);
-	pixman_region32_init_rect(&surface->input, 0, 0,
-				  params->width, params->height);
+	if (params->capture_input) {
+		pixman_region32_init_rect(&surface->input, 0, 0,
+					  params->width, params->height);
+	} else {
+		pixman_region32_init(&surface->input);
+	}
 
 	weston_surface_set_size(surface, params->width, params->height);
 	weston_view_set_position(view, params->x, params->y);

shared/shell-utils.h

@@ -33,6 +33,7 @@ struct weston_curtain_params {
 	void *surface_private;
 	float r, g, b, a;
 	int x, y, width, height;
+	bool capture_input;
 };
 
 struct weston_output *