Keep the handle of SceneHolder before processing events in Core
Keep the handle of SceneHolder before processing events in Core

Change-Id: I042e3c27e5de8fc82f75170e34ebfbea0a79b933

dalihub/dali-adaptor,dalihub/dali-adaptor,dalihub/dali-adaptor,dalihub/dali-adaptor,dalihub/dali-adaptor