Merge "Ensure that velocity tracker is never null." into rvc-dev am:...

Merge "Ensure that velocity tracker is never null." into rvc-dev am: 05df6a58 am: c53ba4e8 am: b453641e

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/11796856

Change-Id: I3ad4c8671698f33f143226453555ade41c04294c