Merge "[Output Switcher] Allow volume adjustment for Guest" into udc-dev am:...

Merge "[Output Switcher] Allow volume adjustment for Guest" into udc-dev am: 0a2ecf1c am: 3a1da8a4 am: 56850831 am: 4d2c122d

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23831003



Change-Id: I5b9177c2ebf58b300703212df02306816d3a8f4f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>