added GtkUpdateScrollbar; folded some code duplicated for horz/vert orientations in a single branch

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@35874 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/window.h

@@ -173,6 +173,10 @@ public:
     virtual void ApplyToolTip( GtkTooltips *tips, const wxChar *tip );
 #endif // wxUSE_TOOLTIPS
 
+    // Call after modifing the value of m_hAdjust or m_vAdjust to bring the
+    // scrolbar in sync (this does not generate any wx events)
+    void GtkUpdateScrollbar(int orient);
+
     // Called from GTK signales handlers. it indicates that
     // the layouting functions have to be called later on
     // (i.e. in idle time, implemented in OnInternalIdle() ).