[gtk+] iconhelper: Short-circuit clear() if it's cleared already

[Timm Bäder <baedert src gnome org>]

commit ce5560a790fe4c20a1c8abe52fd223491129d01a
Author: Timm Bäder <mail baedert org>
Date:   Sat Oct 14 14:58:13 2017 +0200

    iconhelper: Short-circuit clear() if it's cleared already

 gtk/gtkiconhelper.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)
---
diff --git a/gtk/gtkiconhelper.c b/gtk/gtkiconhelper.c
index 51954a7..5fe7689 100644
--- a/gtk/gtkiconhelper.c
+++ b/gtk/gtkiconhelper.c
@@ -85,12 +85,13 @@ _gtk_icon_helper_clear (GtkIconHelper *self)
   g_clear_object (&self->texture);
   g_clear_pointer (&self->rendered_surface, cairo_surface_destroy);
 
-  gtk_image_definition_unref (self->def);
-  self->def = gtk_image_definition_new_empty ();
-
+  if (gtk_image_definition_get_storage_type (self->def) != GTK_IMAGE_EMPTY)
+    {
+      gtk_image_definition_unref (self->def);
+      self->def = gtk_image_definition_new_empty ();
+      gtk_icon_helper_invalidate (self);
+    }
   self->icon_size = GTK_ICON_SIZE_INVALID;
-
-  gtk_icon_helper_invalidate (self);
 }
 
 void