Merge "Make DreamActivity no history" into tm-qpr-dev am: 8a0d4e39 am: 49f99abf am: 9b3dcab9

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/21518427



Change-Id: I4ffcb210239bcdce049973706c141e6751669b4a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>