Merge: Introduce UpdateLocks

An "UpdateLock" works similarly to a wake lock in API: the caller is
providing a hint to the OS that now is not a good time to interrupt
the user/device in order to do intrusive work like applying OTAs.
This is particularly important for headless or kiosk-like products
where ordinarily the update process will be automatically scheduled
and proceed without user or administrator intervention.

UpdateLocks require that the caller hold the new signatureOrSystem
permission android.permission.UPDATE_LOCK.  acquire() and release()
will throw security exceptions if this is not the case.

The "is now convenient?" state is expressed to interested parties
by way of a sticky broadcast sent only to registered listeners.  The
broadcast is protected; only the system can send it, so listeners
can trust it to be accurate.  The broadcast intent also includes a
timestamp (System.currentTimeMillis()) to help inform listeners that
wish to implement scheduling policies based on when the device became
idle.

The API change here is a tiny one: a dump(PrintWriter) method has been
added to the TokenWatcher class to facilitate getting information out
of it for dumpsys purposes.  UpdateLock itself is still @hide.

Bug 5543442

Change-Id: I3709c831fc1883d7cb753cd2d3ee8e10a61e7e48

0 files changed, 0 insertions, 0 deletions