Merge "Add internal WM API for registering activity interceptors." into sc-v2-dev am: aeb53657df am: d35638dce2

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15983741

Change-Id: I35a7d6a6bb0846efc96424d9d228e60952aab234