- Disable drop targets when picking up a task that can’t be docked, and
show toast notifying user (for now)
- When a task is docked, update the task headers for non-dockable tasks
to indicate that they don’t support multi window. Update these
headers every time the multi window state changes.
Bug: 26774190
Change-Id: I020dcbac9b1230dba166eecaa12366986e684f9e