Merge "Make mCurrentPipTaskToken null when app crashes" into udc-dev am: 2a2a1b1266

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24044846

Change-Id: I248cd0ed6f1324fb77745133ffd401eb701714e6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>