[gtk+] treev view column: Use GdkEvent API

[Carlos Garnacho <carlosg src gnome org>]

commit 208a85c3fe939261566e8ba17046836f5f9c7697
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Aug 26 14:29:52 2017 -0400

    treev view column: Use GdkEvent API

 gtk/gtktreeviewcolumn.c |   15 ++++++---------
 1 files changed, 6 insertions(+), 9 deletions(-)
---
diff --git a/gtk/gtktreeviewcolumn.c b/gtk/gtktreeviewcolumn.c
index 50cd939..3fe55c9 100644
--- a/gtk/gtktreeviewcolumn.c
+++ b/gtk/gtktreeviewcolumn.c
@@ -1018,18 +1018,19 @@ gtk_tree_view_column_button_event (GtkWidget *widget,
   GtkTreeViewColumn        *column = (GtkTreeViewColumn *) data;
   GtkTreeViewColumnPrivate *priv   = column->priv;
   GdkEventType              event_type;
+  guint button;
+  gdouble x, y;
 
   g_return_val_if_fail (event != NULL, FALSE);
 
   event_type = gdk_event_get_event_type (event);
+  gdk_event_get_button (event, &button);
+  gdk_event_get_coords (event, &x, &y);
 
   if (event_type == GDK_BUTTON_PRESS &&
       priv->reorderable &&
-      ((GdkEventButton *)event)->button == GDK_BUTTON_PRIMARY)
+      button == GDK_BUTTON_PRIMARY)
     {
-      gdouble x, y;
-
-      gdk_event_get_coords (event, &x, &y);
       priv->maybe_reordered = TRUE;
       priv->drag_x = x;
       priv->drag_y = y;
@@ -1042,11 +1043,7 @@ gtk_tree_view_column_button_event (GtkWidget *widget,
   
   if (event_type == GDK_MOTION_NOTIFY &&
       priv->maybe_reordered &&
-      (gtk_drag_check_threshold (widget,
-                                priv->drag_x,
-                                priv->drag_y,
-                                (gint) ((GdkEventMotion *)event)->x,
-                                (gint) ((GdkEventMotion *)event)->y)))
+      gtk_drag_check_threshold (widget, priv->drag_x, priv->drag_y, (gint) x, (gint) y))
     {
       priv->maybe_reordered = FALSE;
       _gtk_tree_view_column_start_drag (GTK_TREE_VIEW (priv->tree_view), column,