[androidkit] add custom view for easy navigation between demos

Change-Id: I1614e105eb274738dc1f9eab6674e28afbbe6698
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/401079
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Jorge Betancourt <jmbetancourt@google.com>
3 files changed