Factor out wxDataViewRendererBase::NotifyEditingStarted()

Reuse the same code from the generic and native GTK and OS X implementations
of wxDataViewCtrl instead of triplicating it.

This fixes a small discrepancy between the wxOSX version, which didn't see the
model pointer correctly in the generated event, and all the others, but mainly
paves way for future improvements.

include/wx/dvrenderers.h

@@ -180,6 +180,9 @@ public:
     // wxDVR_DEFAULT_ALIGNMENT.
     int GetEffectiveAlignment() const;
 
+    // Send wxEVT_DATAVIEW_ITEM_EDITING_STARTED event.
+    void NotifyEditingStarted(const wxDataViewItem& item);
+
 protected:
     // These methods are called from PrepareForItem() and should do whatever is
     // needed for the current platform to ensure that the item is rendered

src/common/datavcmn.cpp

@@ -703,15 +703,22 @@ bool wxDataViewRendererBase::StartEditing( const wxDataViewItem &item, wxRect la
     m_editorCtrl->SetFocus();
 #endif
 
-    // Now we should send Editing Started event
+    NotifyEditingStarted(item);
+
+    return true;
+}
+
+void wxDataViewRendererBase::NotifyEditingStarted(const wxDataViewItem& item)
+{
+    wxDataViewColumn* const column = GetOwner();
+    wxDataViewCtrl* const dv_ctrl = column->GetOwner();
+
     wxDataViewEvent event( wxEVT_DATAVIEW_ITEM_EDITING_STARTED, dv_ctrl->GetId() );
-    event.SetDataViewColumn( GetOwner() );
+    event.SetDataViewColumn( column );
     event.SetModel( dv_ctrl->GetModel() );
     event.SetItem( item );
     event.SetEventObject( dv_ctrl );
     dv_ctrl->GetEventHandler()->ProcessEvent( event );
-
-    return true;
 }
 
 void wxDataViewRendererBase::DestroyEditControl()

src/gtk/dataview.cpp

@@ -1767,12 +1767,8 @@ wxgtk_renderer_editing_started( GtkCellRenderer *WXUNUSED(cell), GtkCellEditable
 
     wxDataViewColumn *column = wxrenderer->GetOwner();
     wxDataViewCtrl *dv = column->GetOwner();
-    wxDataViewEvent event( wxEVT_DATAVIEW_ITEM_EDITING_STARTED, dv->GetId() );
-    event.SetDataViewColumn( column );
-    event.SetModel( dv->GetModel() );
     wxDataViewItem item(dv->GTKPathToItem(wxGtkTreePath(path)));
-    event.SetItem( item );
-    dv->HandleWindowEvent( event );
+    wxrenderer->NotifyEditingStarted(item);
 
     if (GTK_IS_CELL_EDITABLE(editable))
     {

src/osx/cocoa/dataview.mm

@@ -1886,22 +1886,20 @@ outlineView:(NSOutlineView*)outlineView
     wxDataViewColumn* const
         col([static_cast<wxDVCNSTableColumn*>(tableColumn) getColumnPointer]);
 
-    wxDataViewCtrl* const dvc = implementation->GetDataViewCtrl();
-
-
     // stop editing of a custom item first (if necessary)
     dvc->FinishCustomItemEditing();
 
     // now, send the event:
-    wxDataViewEvent
-        event(wxEVT_DATAVIEW_ITEM_EDITING_STARTED,dvc->GetId());
-
-    event.SetEventObject(dvc);
-    event.SetItem(
-            wxDataViewItemFromItem([self itemAtRow:currentlyEditedRow]));
-    event.SetColumn(dvc->GetColumnPosition(col));
-    event.SetDataViewColumn(col);
-    dvc->GetEventHandler()->ProcessEvent(event);
+    wxDataViewRenderer* const renderer = col->GetRenderer();
+    if ( renderer )
+    {
+        renderer->NotifyEditingStarted
+                  (
+                    wxDataViewItemFromItem([self itemAtRow:currentlyEditedRow])
+                  );
+    }
+    //else: we should always have a renderer but don't crash if for some
+    //      unfathomable reason we don't have it
 }
 
 -(void) textDidEndEditing:(NSNotification*)notification