Merge "Only register stationary detector while idle" into sc-qpr1-dev am: 65f1d1a5 am: 307c5490

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15639364

Change-Id: I9065c9554dc8445e9fc0951dab6182cf5c1daffc