Close the shortcuts container in various places.

- Mostly everywhere folders are closed
- Implements DragListener so we can close the container when dragging
  the original icon or shortcuts from the container. We actually just
  hide the container in onDragStart() and really remove it in
  onDragEnd(). This avoids interfering with touch events and thus
  allows us to remove the hack of explicitly setting the DragLayer's
  controller when dragging shortcuts (since it will do it on intercept).

Bug: 30080537

Change-Id: Iccc2afba2a990a613bc588d57c4d8c1b7c65224b