base

Framework support for Android Dreams.

A Dream is an activity that is launched by the window
manager after a specified idle time. You might think of this
as a "screen saver", but with the same capacity for
interactivity as any other application.

The window manager maintains a timer (like the screen lock
timer) that is reset on userActivity; the timer is suspended
during wakelocks and when the screen is off.

When the timer elapses, the user's preferred dream module is
launched (by reading Settings.Secure.DREAM_COMPONENT, which
is configured through the Settings app UI).

Like a dock app, the user can install new dreams and a
single application package may contain multiple dream
activities. Unlike the dock mode, however, there is no
"screensaver mode" for the system to manage. This allows us
to offer the user the ability to run a dream at any time, in
addition to making the overall mechanism quite simple.

There is no public API for this facility.

There is, however, a useful/recommended base class for dream
activities in the support library (change I4559a958).

Change-Id: Ied691856f88cfa38a7aca496d015f9a595da72f2