view iface: remove unused will_add_event

ECalDataModelSubscriber interface notify each view only about the events
beloging to the subscribed range so there's no need of checking if the
event widget will be added.
The safety check of not adding the same widget twice its stil being made
on each GtkContainer::add implementation.

src/gcal-view.c

@@ -307,25 +307,3 @@ gcal_view_clear (GcalView *view)
 
   GCAL_VIEW_GET_INTERFACE (view)->clear (view);
 }
-
-/**
- * gcal_view_will_add_event:
- * @view: a #GcalView
- * @event: a #GcalEventWidget
- *
- * Check the ranges of dates and the existence of the widget in
- * in the view already
- *
- * Returns: %TRUE if the date of the widget fall inside the range and
- *          the widget isn't already on the view, %FALSE otherwise
- **/
-gboolean
-gcal_view_will_add_event (GcalView        *view,
-                          GcalEventWidget *event)
-{
-  g_return_val_if_fail (GCAL_IS_VIEW (view), FALSE);
-  g_return_if_fail (GCAL_VIEW_GET_INTERFACE (view)->will_add_event);
-
-  return GCAL_VIEW_GET_INTERFACE (view)->will_add_event (view,
-                                                         event);
-}