[gtk/wip/baedert/for-master: 23/23] cssvalue: Add class check to transition

[Timm Bäder <baedert src gnome org>]

commit f78c16747668c62ed1859ed5a6d9dcf5058f8b1a
Author: Timm Bäder <mail baedert org>
Date:   Wed May 13 08:06:51 2020 +0200

    cssvalue: Add class check to transition
    
    In b25f93e24c78c639b4fd869d4e42ba9161781c12 we removed the code
    comparing the transition functions, but we didn't add any other check
    back.
    
    Fixes #2740

 gtk/gtkcssvalue.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/gtk/gtkcssvalue.c b/gtk/gtkcssvalue.c
index b48f82a3c7..b5bcb91369 100644
--- a/gtk/gtkcssvalue.c
+++ b/gtk/gtkcssvalue.c
@@ -263,6 +263,9 @@ _gtk_css_value_transition (GtkCssValue *start,
   gtk_internal_return_val_if_fail (start != NULL, FALSE);
   gtk_internal_return_val_if_fail (end != NULL, FALSE);
 
+  if (start->class != end->class)
+    return NULL;
+
   if (progress == 0)
     return _gtk_css_value_ref (start);