1) Do not pulse notification LED when screen is on. 2) Pulse once on new notification if Settings.System.NOTIFICATION_LIGHT_PULSE is false, otherwise pulse persistently while screen is off. Fixes part of bug b/2238250 (trackball should pulse occasionally to indicate new email) Change-Id: Icc49422a4e9d14412fc159a8e2596503a85bac51 Signed-off-by: Mike Lockwood <lockwood@android.com>