Add GtkNumerableIcon

This is a subclass of GEmblemedIcon that can show a number or
short string as an emblem, overlayed on top of another emblem.

Written by Cosimo Cecchi
https://bugzilla.gnome.org/show_bug.cgi?id=637169

gtk/gtkicontheme.c

@@ -45,6 +45,7 @@
 #include "gtkbuiltincache.h"
 #include "gtkintl.h"
 #include "gtkmain.h"
+#include "gtknumerableiconprivate.h"
 #include "gtksettings.h"
 #include "gtkprivate.h"
 
@@ -3799,6 +3800,9 @@ gtk_icon_theme_lookup_by_gicon (GtkIconTheme       *icon_theme,
       GList *list, *l;
       GtkIconInfo *emblem_info;
 
+      if (GTK_IS_NUMERABLE_ICON (icon))
+        _gtk_numerable_icon_set_background_icon_size (GTK_NUMERABLE_ICON (icon), size / 2);
+
       base = g_emblemed_icon_get_icon (G_EMBLEMED_ICON (icon));
       info = gtk_icon_theme_lookup_by_gicon (icon_theme, base, size, flags);
       if (info)