[gtk/wip/otte/reftests: 5/6] reftests: Fix border-image-excess-size.ui test

[Benjamin Otte <otte src gnome org>]

commit ee843d51fbac80b79707b660aeabf55b1185cdde
Author: Benjamin Otte <otte redhat com>
Date:   Thu Mar 28 00:39:36 2019 +0100

    reftests: Fix border-image-excess-size.ui test
    
    The old reftests drew an opaque image, the new image is transparent.
    
    This test drew the reference image as black and the test as transparent
    black, and those are now different.

 testsuite/reftests/border-image-excess-size.css | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/testsuite/reftests/border-image-excess-size.css b/testsuite/reftests/border-image-excess-size.css
index 57ee781428..b41344cfce 100644
--- a/testsuite/reftests/border-image-excess-size.css
+++ b/testsuite/reftests/border-image-excess-size.css
@@ -10,6 +10,10 @@ toolbar {
   border-radius: 0;
 }
 
+grid {
+  background-color: #000;
+}
+
 grid * {
   background-color: lime;
   border-style: none;