[automerger skipped] Add ListenerSet and use in places which currently copy-on-iterate. am: 6a9caed0 am: 93b06dea -s ours

am skip reason: Merged-In Ic1320b4f6c424322451f7def11346865bf878f99 with SHA-1 30dd32ba is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/16150891

Change-Id: I7e43897d642aba1996993c5f53ceae0ebe753e0f