Add support for locking the screen when the lid is closed

This commit adds configurable support for lockscreen
behaviour when the user has a device cover/lid.  This
is intended for lids with a viewing window so that the
user can see the time and interact with apps via the
window.

Change-Id: Id71883f66d1a180c4732912b3b59cabf9f4d7b6e
5 files changed