Moved more code from wxDataViewCtrl to wxDataViewCtrlInternal.

Add new special API for wxDataViewVirtualIndexModel::Reset() as
wxDataViewModel::Clear is something different and needs a different, two
step API under GTK+, one for destroying the current view and one for
rereading the new contents.
Added ::BeforeReset() and ::AfterReset() notifications for that purpose.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65533 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/dataview.h

@@ -195,11 +195,9 @@ private:
 
     friend class wxDataViewCtrlDCImpl;
     friend class wxDataViewColumn;
-    friend class wxGtkDataViewModelNotifier;
     friend class wxDataViewCtrlInternal;
 
     GtkWidget               *m_treeview;
-    wxDataViewModelNotifier *m_notifier;
     wxDataViewCtrlInternal  *m_internal;
     wxDataViewColumnList     m_cols;