Active Display: Center the icon

Change-Id: I2f442a5ae2de0d4074ccfea96d37f8faa769e509
Signed-off-by: Lokesh Chamane <lokesh.c703@gmail.com>
Only show status bar blocker view if nav bar is translucent.

It's the background drawable of the translucent nav bar that makes the
blocker view necessary (as the background creates a visual 'gap' between
status bar and visual start of the nav bar), so if the nav bar isn't
translucent, there's no need for the view.

Change-Id: I684c8d24abe3d4393ae7db88fe5023aa65836164