remove default looper flag, rely on clients to opt-in

Bug: skia:4783
Change-Id: I232ec6fa10287b6e07849d596b93cc997e0de052
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/229280
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
3 files changed