Merge "SupportLeanbackShowcase: bring gradle, build tools, lib up to date am: 15f5a3351f am: 302ab270d6" into nyc-mr1-dev-plus-aosp
am: f46db09d19

* commit 'f46db09d190e809e204c4d0a319cbef9a6a87ea7':

Change-Id: I21adb88567684df05c619b5f4dd3075e68c482c1