Merge "Adding optional block to run before screenshot" into udc-dev am: a6550a83 am: aa7801da am: dc9f549b

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



Change-Id: I5a47015cbdf9e452935b4f477a07d557d65cdeed
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>