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: 0e0887f6

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

Change-Id: I8b2b5394925a6a77d18fcde2ccb95a4a6aa73148