Merge "Remove volume_separate_notification flag" into udc-dev am: 485a8116 am: 197daf98

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23221865



Change-Id: I5bdddaf890efeba863b4101857c99674129a43ca
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>