Merge "Ensure reparent activity TaskFragment is always within the same Task"...

Merge "Ensure reparent activity TaskFragment is always within the same Task" into tm-dev am: 74beca1b am: 1be337bf am: ca2881f4 am: 704ed4d4

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18330765



Change-Id: I3b048adec072f93cd108da7be5bd2d1a61666dcc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>