Merge "Allow to register RENDER AudioMix pointing to previously registered...

Merge "Allow to register RENDER AudioMix pointing to previously registered LOOPBACK AudioMix." into udc-dev am: 55825ec1 am: beac8043 am: 8d415691 am: b56aad7a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/23693534



Change-Id: Iff9707daa9b79b8591f68b603252fb7382baa349
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>