Task auto complete only when all predecessors complete

Add/Change Tracking mode that will allow for a task to auto complete only when all predecessors complete.

Business Justification:
The current implementation of auto complete tracking mode will auto complete based on the planned date and does not account for slips in a schedule.

Use Case:
If Task 1 (due on 1/1/2018, tracking mode "User Must Update") is a predecessor of Task 2 (due on 1/1/2018, duration 0, tracking mode "Auto Complete") if Task 1 slips, the current implementation would close Task 2 but Task 1 would show late. What seems more useful is that Task 2 would not close until Task 1 is closed even in the event of a slip in Task 1.