DO NOT MERGE -- Use focused activity value when moving task back

When task is moved back we need to adjust currently focused activity
and sent currently resumed record from ActivityStack. However if this
happens when device is locked, resumed activity record will be null.
Need to used currently focused record from service instead.

Bug: 32172829
Change-Id: I2de9bc4135663ab45af859f21e9e92562deb44d4