Merge "Adding optional block to run before screenshot" into udc-dev am: a6550a83 am: 3523cdac am: 15942c7f am: e7070aaa

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/23356977



Change-Id: I87649f34d29f5cc5bd9c20ff1bcf543f5004eb97
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>