compositor: Keep fade surface around while we're fading
This removes more special cases from weston_output_repaint() and we
avoid creating and destroying the surface for each animation frame.
We gain another special case in weston_compositor_top(), but that's
less of a problem, and we'll fix that later.
diff --git a/src/compositor.h b/src/compositor.h
index e318d7b..fe7176a 100644
--- a/src/compositor.h
+++ b/src/compositor.h
@@ -182,6 +182,7 @@
struct {
struct weston_spring spring;
struct weston_animation animation;
+ struct weston_surface *surface;
} fade;
uint32_t state;