Merge "Add nullability annotations" am: 539821c978 am: 97350573b9
am: c66eb1e12e

Change-Id: I43088399da1d81556ab903ef1ca716439129f00d
tree: 3b477e6d5de0d8b8cc5c3a4b3d1f391c569fc9fd
  1. core/
  2. services/
  3. tests/