[gtkmm] Gdk::Window: Remove ensure_native().

[Murray Cumming <murrayc src gnome org>]

commit 01285fc72e72e2bae21e1ce1d18768010e69296c
Author: Murray Cumming <murrayc murrayc com>
Date:   Sat Dec 17 22:17:01 2016 +0100

    Gdk::Window: Remove ensure_native().
    
    Because it was removed from GTK+:
    https://git.gnome.org/browse/gtk+/commit/?id=5bf28a386937847a171435bf55be16769565e402

 gdk/src/window.hg |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/gdk/src/window.hg b/gdk/src/window.hg
index d3e7dd2..8ee3bf8 100644
--- a/gdk/src/window.hg
+++ b/gdk/src/window.hg
@@ -120,7 +120,6 @@ public:
 
   _WRAP_METHOD(void scroll(int dx, int dy), gdk_window_scroll)
   _WRAP_METHOD(void move_region(const ::Cairo::RefPtr< ::Cairo::Region>& region, int dx, int dy), 
gdk_window_move_region)
-  _WRAP_METHOD(bool ensure_native(), gdk_window_ensure_native)
 
   _WRAP_METHOD(void shape_combine_region(const ::Cairo::RefPtr< ::Cairo::Region>& shape_region, int offset_x 
= 0, int offset_y = 0), gdk_window_shape_combine_region)
   _WRAP_METHOD(void set_child_shapes(), gdk_window_set_child_shapes)