- The task overlay activity should only exist when there are activities present in the task. When the last such activity is finished, we should remove the whole task entirely including the task overlay. - Exposing the task overlay apis to CTS Bug: 36507456 Test: android.server.cts.ActivityManagerPinnedStackTests Test: #testFinishPipActivityWithTaskOverlay Change-Id: I1dabe7782fb6769a90d832664e8052be158041e1