return RET_CANCEL for ui-previewer

Change-Id: Ic175ae730dc67ae28bb52ee503ee5e572bb4cabc
coverity#1237353 Unchecked dynamic_cast

Change-Id: If25d29eaa788e70972fd0cbbf3d03f4d05862f24
coverity#708008 Uninitialized scalar field

Change-Id: I425b1d822d98cbc28a1d99b41379b0dc5d8e6193
coverity#1237351 Logically dead code

Change-Id: Ia82d8d137c5f36cc48826cc851d6f00626e978aa
coverity#1237355 Dereference null return value

Change-Id: I66956979c494f96f76eb0a7840f28c8edc91d816
coverity#1237357 Uncaught exception

Change-Id: Ie116e0070792c59893ed0b4f41bcf9831400deb9
coverity#704947 Dereference after null check

Change-Id: Id6eb50de48b8a674d7b48d1256b1529637155eb1