[gthumb/gthumb-3-10] webp: unref cairo surface to fix memory leak

[Paolo Bacchilega <paobac src gnome org>]

commit 6de3726ff7782743ec2bcfb1384da5827e29272c
Author: Jürg Billeter <j bitron ch>
Date:   Wed Sep 1 11:10:26 2021 +0200

    webp: unref cairo surface to fix memory leak
    
    `gth_image_set_cairo_surface()` takes a reference.

 extensions/cairo_io/cairo-image-surface-webp.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/extensions/cairo_io/cairo-image-surface-webp.c b/extensions/cairo_io/cairo-image-surface-webp.c
index 3bcfb8fe..4c0c22c7 100644
--- a/extensions/cairo_io/cairo-image-surface-webp.c
+++ b/extensions/cairo_io/cairo-image-surface-webp.c
@@ -132,6 +132,7 @@ _cairo_image_surface_create_from_webp (GInputStream  *istream,
        cairo_surface_mark_dirty (surface);
        if (cairo_surface_status (surface) == CAIRO_STATUS_SUCCESS)
                gth_image_set_cairo_surface (image, surface);
+       cairo_surface_destroy (surface);
 
        WebPIDelete (idec);
        WebPFreeDecBuffer (&config.output);