[gtk] Revert "gl renderer: ops_set_modelview is (transfer full)"

[Timm Bäder <baedert src gnome org>]

commit 5f21c45f7507575ef5069f18a854ed7fb895e940
Author: Timm Bäder <mail baedert org>
Date:   Sun Jul 21 12:43:00 2019 +0200

    Revert "gl renderer: ops_set_modelview is (transfer full)"
    
    This reverts commit e904c49e8aaebc266bac9024b13389e4521bbbaa.
    
    This breaks HiDPI setups, i.e. setups where the call to
    ops_set_modelview does not end up with a NULL transform.

 gsk/gl/gskglrenderops.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gsk/gl/gskglrenderops.c b/gsk/gl/gskglrenderops.c
index 057674ddbc..7c02442d08 100644
--- a/gsk/gl/gskglrenderops.c
+++ b/gsk/gl/gskglrenderops.c
@@ -401,7 +401,7 @@ ops_set_modelview (RenderOpBuilder *builder,
   g_array_set_size (builder->mv_stack, builder->mv_stack->len + 1);
   entry = &g_array_index (builder->mv_stack, MatrixStackEntry, builder->mv_stack->len - 1);
 
-  entry->transform = transform;
+  entry->transform = gsk_transform_ref (transform);
 
   entry->metadata.dx_before = builder->dx;
   entry->metadata.dy_before = builder->dy;