Merge "Revert "Update volume behavior documentation."" into udc-dev am: 50ed6f3e am: 10c2a19f

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22164167



Change-Id: I51814b183c2166884fe72779f141fe225f0372b6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>