[gtk/wip/baedert/css-values: 3/3] css: Use a singleton for builtin image values

[Timm Bäder <baedert src gnome org>]

commit 9199b54dc4101f8675daf282cc308d41850f12cb
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Jan 9 19:50:53 2020 -0500

    css: Use a singleton for builtin image values
    
    There's only a singleton builtin image, so there
    is not much point in creating 1000s of values holding
    the it. Just make it a singleton.

 gtk/gtkcssimagevalue.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
---
diff --git a/gtk/gtkcssimagevalue.c b/gtk/gtkcssimagevalue.c
index 1a628a568f..8ddc88b7a0 100644
--- a/gtk/gtkcssimagevalue.c
+++ b/gtk/gtkcssimagevalue.c
@@ -20,6 +20,7 @@
 #include "gtkcssimagevalueprivate.h"
 
 #include "gtkcssimagecrossfadeprivate.h"
+#include "gtkcssimagebuiltinprivate.h"
 
 struct _GtkCssValue {
   GTK_CSS_VALUE_BASE
@@ -137,11 +138,20 @@ GtkCssValue *
 _gtk_css_image_value_new (GtkCssImage *image)
 {
   static GtkCssValue none_singleton = { &GTK_CSS_VALUE_IMAGE, 1, NULL };
+  static GtkCssValue builtin_singleton = { &GTK_CSS_VALUE_IMAGE, 1, NULL };
   GtkCssValue *value;
 
   if (image == NULL)
     return _gtk_css_value_ref (&none_singleton);
 
+  if (GTK_IS_CSS_IMAGE_BUILTIN (image))
+    {
+      if (builtin_singleton.image == NULL)
+        builtin_singleton.image = image;
+
+       return _gtk_css_value_ref (&builtin_singleton);
+    }
+
   value = _gtk_css_value_new (GtkCssValue, &GTK_CSS_VALUE_IMAGE);
   value->image = image;