[librsvg] benches: shorten code

[Paolo Borelli <pborelli src gnome org>]

commit a262cc44fb3a5e12be074cecb15cda7fbe246429
Author: Paolo Borelli <pborelli gnome org>
Date:   Fri Jan 17 10:39:29 2020 +0100

    benches: shorten code

 rsvg_internals/benches/box_blur.rs | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)
---
diff --git a/rsvg_internals/benches/box_blur.rs b/rsvg_internals/benches/box_blur.rs
index cefd20ae..28f1e37c 100644
--- a/rsvg_internals/benches/box_blur.rs
+++ b/rsvg_internals/benches/box_blur.rs
@@ -19,15 +19,13 @@ fn bench_box_blur(c: &mut Criterion) {
     c.bench_function_over_inputs(
         "box_blur 9",
         |b, &(vertical, alpha_only)| {
-            let input_surface =
-                cairo::ImageSurface::create(cairo::Format::ARgb32, SURFACE_SIDE, SURFACE_SIDE)
-                    .unwrap();
             let surface_type = if alpha_only {
                 SurfaceType::AlphaOnly
             } else {
                 SurfaceType::SRgb
             };
-            let input_surface = SharedImageSurface::wrap(input_surface, surface_type).unwrap();
+            let input_surface =
+                SharedImageSurface::empty(SURFACE_SIDE, SURFACE_SIDE, surface_type).unwrap();
 
             let mut output_surface =
                 cairo::ImageSurface::create(cairo::Format::ARgb32, SURFACE_SIDE, SURFACE_SIDE)