Add item<->row mapping helpers to wxDataViewListCtrl.

These are commonly needed when using wxDataViewListCtrl, yet they were
only available in wxDataViewIndexListModel.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65121 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/dataview.h

@@ -1754,6 +1754,21 @@ public:
     const wxDataViewListStore *GetStore() const;
     //@}
 
+    /**
+        Returns the position of given @e item or wxNOT_FOUND if it's
+        not a valid item.
+
+        @since 2.9.2
+     */
+    int ItemToRow(const wxDataViewItem &item) const;
+
+    /**
+        Returns the wxDataViewItem at the given @e row.
+
+        @since 2.9.2
+     */
+    wxDataViewItem RowToItem(int row) const;
+
     /**
         @name Column management functions
     */