Merge "Revert "Do not retain album art in NotificationMediaManager if unused"" into udc-dev am: bf2a7c7f am: 8d96d2a9

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/22718680



Change-Id: I3a51291ee8211d09c5717b6751dc50919ab22e80
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>