Merge "Make DreamActivity no history" into tm-qpr-dev am: 8a0d4e3977 am: 49f99abf96

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

Change-Id: I94fcdcc347f7c111316ae5ae2487066b04dcd543
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>