[gtk+/wip/baedert/gl: 11/94] gl driver: Make some members const

[Timm Bäder <baedert src gnome org>]

commit 0c71745a02c4db7afaf90e11bc2cb20aa40b9611
Author: Timm Bäder <mail baedert org>
Date:   Thu Nov 9 10:55:14 2017 +0100

    gl driver: Make some members const

 gsk/gskgldriver.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/gsk/gskgldriver.c b/gsk/gskgldriver.c
index 41c6f6c..dbc3977 100644
--- a/gsk/gskgldriver.c
+++ b/gsk/gskgldriver.c
@@ -45,10 +45,10 @@ struct _GskGLDriver
   GHashTable *textures;
   GHashTable *vaos;
 
-  Texture *bound_source_texture;
-  Texture *bound_mask_texture;
-  Vao *bound_vao;
-  Fbo *bound_fbo;
+  const Texture *bound_source_texture;
+  const Texture *bound_mask_texture;
+  const Vao *bound_vao;
+  const Fbo *bound_fbo;
 
   int max_texture_size;