This change reuses KeyguardViewMediator for the new Keyguard
implementation in status bar. KeyguardViewManager is replaced by
StatusBarKeyguardManager which handles adding the view, setting the
state etc. StatusBarWindowManager is introduced to managed the window
of the status bar, which has the logic of both the old Keyguard window
and the old status bar window. In the current implementation, Keyguard
gets displayed like it would be in the bouncer state, but that's likely
to change in the future. Also, setHidden in IKeyguardService is also
renamed to setOccluded, as the word hidden interferes with the
terminology when dismissing the Keyguard.
Bug: 13635952
Change-Id: I1c5d5a49d810d8532089f464cb2efe35e577f517
