Merge "Document the expected value of volume control id parameter" into...

Merge "Document the expected value of volume control id parameter" into udc-dev am: ec281057 am: b5d36b9c

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22380604



Change-Id: I6033f766c0e093f244bf6753d69347bc04389103
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>