Merge "Document the limitation to a hundred callbacks." am: f60ed54d33 am: 363fb9fef9

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1313813

Change-Id: I84b1e39503feddc914b61d4e8bd35953e92ac270
tree: 97364c6e7191de960bca63829f950b619959e33c
  1. core/
  2. services/
  3. tests/