Merge "Clear set of "unseen" notifications when unlocked" into tm-qpr-dev am: 9d2413c996 am: 9cf90b5670

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21407765

Change-Id: I6a17dba47c8e48a5e1e9e31729bab75fe287e9ab
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>