Fixing some Recents landscape issues.

- Tasks were drawing under the navigation in landscape since we did 
  not account for the nav bar space
- Fixing issue with tiny tasks in landscape
- Fixing issue where pooled views were not being measured or laid out
  after resizing.
- Fixing issue where the stack scroll would have out of bounds when 
  tasks were resized (we animate them into bounds)

Change-Id: Id301dc6891e7ff2692cb040a7df1a5a854ac84a3