Add a persistence mechanism for panels' packages am: e192a439

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/20928108



Change-Id: I8a577b1494e3145bad509516fbdb2d7124e88061
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>