Ask the policy controller for launching activities

Ask the policy controller whether an activity can be displayed on the
virtual display when it is going to launch or reparent.

Also notify the policy controller the activity changes on the virtual
display.

Bug: 201712607
Test: atest DisplayWindowPolicyControllerHelperTests
      atest ActivityRecordTests
      atest ActivityTaskSupervisorTests
      atest TaskTests
      atest TaskFragmentTest
      atest WindowManagerServiceTests

Change-Id: I11fcc38782b21ccb2f0474777242dbf5901c59e1