css: Add a :dnd pseudoclass

This will be used for drag highlighting.

gtk/gtkcssselector.c

@@ -744,7 +744,8 @@ print_pseudoclass_state (const GtkCssSelector *selector,
     "dir(rtl)",
     "link",
     "visited",
-    "checked"
+    "checked",
+    "dnd"
   };
   guint i;
 
@@ -1188,7 +1189,8 @@ parse_selector_pseudo_class (GtkCssParser   *parser,
     { "dir(rtl)",     GTK_STATE_FLAG_DIR_RTL, },
     { "link",         GTK_STATE_FLAG_LINK, },
     { "visited",      GTK_STATE_FLAG_VISITED, },
-    { "checked",      GTK_STATE_FLAG_CHECKED, }
+    { "checked",      GTK_STATE_FLAG_CHECKED, },
+    { "dnd"    ,      GTK_STATE_FLAG_DND, }
   };
   guint i;
 

gtk/gtkenums.h

@@ -857,6 +857,7 @@ typedef enum
  * @GTK_STATE_FLAG_LINK: Widget is a link. Since 3.12
  * @GTK_STATE_FLAG_VISITED: The location the widget points to has already been visited. Since 3.12
  * @GTK_STATE_FLAG_CHECKED: Widget is checked. Since 3.14
+ * @GTK_STATE_FLAG_DND: Widget is highlighted as a drop target for DND. Since 3.20
  *
  * Describes a widget state. Widget states are used to match the widget
  * against CSS pseudo-classes. Note that GTK extends the regular CSS
@@ -876,7 +877,8 @@ typedef enum
   GTK_STATE_FLAG_DIR_RTL      = 1 << 8,
   GTK_STATE_FLAG_LINK         = 1 << 9,
   GTK_STATE_FLAG_VISITED      = 1 << 10,
-  GTK_STATE_FLAG_CHECKED      = 1 << 11
+  GTK_STATE_FLAG_CHECKED      = 1 << 11,
+  GTK_STATE_FLAG_DND          = 1 << 12
 } GtkStateFlags;
 
 /**

gtk/gtkwidgetprivate.h

@@ -34,7 +34,7 @@
 
 G_BEGIN_DECLS
 
-#define GTK_STATE_FLAGS_BITS 12
+#define GTK_STATE_FLAGS_BITS 13
 
 struct _GtkWidgetPrivate
 {