[automerger skipped] Merge "Allow null subscriberId in NetworkStatsManager." into pi-dev
am: d1b38d88cd  -s ours

Change-Id: I6e8983cc087a8a42e1404bb5f99bcd297b0ff313
tree: 1ca633c6b1b1803de818717916267b418774baa9
  1. core/
  2. services/
  3. tests/