Merge "Provide config for customize the showing strategy of back target." into...

Merge "Provide config for customize the showing strategy of back target." into udc-dev am: b11b27d4 am: 850e4d6e

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21578380



Change-Id: I5636bd37633679c982325019009aefd6703a9b1a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>