Registers a callback that's fired when a shape is erased.
Returns an ID which can be passed to unlisten() to unregister the callback.
The ui.Map.DrawingTools instance.
The callback to fire when a shape is erased. The callback is passed three parameters: the removed ee.Geometry, the GeometryLayer from which the geometry was removed, and the ui.Map.DrawingTools widget that the event listener is bound to.