[androidkit] Add fling support to cube demo

Change-Id: Id3c2eb72e70a3c9c2181c8aff7770aafa7a520d3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/412236
Reviewed-by: Jorge Betancourt <jmbetancourt@google.com>
Commit-Queue: Florin Malita <fmalita@google.com>
2 files changed