Merge "Add support for multiple animation tracks" into udc-dev am: e0d73107b6 am: dcdf427035

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22694546

Change-Id: Icd78e8c7a9ca02dabca7e7ec50138cd18c5eba24
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>