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

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



Change-Id: I850caa3a3424b3e6074349bdc009e8e7917c0964
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>