Adding graphviz source for idling state machine.

 * Keeps track of device idleness and drives low power mode based on that.

 *

 * Test: atest com.android.server.DeviceIdleControllerTest

 *

 * Current idling state machine (as of Android 9 Pie). This can be visualized using Graphviz:

   digraph {

     subgraph deep {

       label="deep";

       STATE_ACTIVE [label="STATE_ACTIVE\nScreen on OR Charging OR Alarm going off soon"]

       STATE_INACTIVE [label="STATE_INACTIVE\nScreen off AND Not charging"]

       STATE_IDLE_PENDING [

         label="STATE_IDLE_PENDING\nSignificant motion monitoring turned on"

       ]

       STATE_SENSING [label="STATE_SENSING\nMonitoring for ANY motion"]

       STATE_LOCATING [

         label="STATE_LOCATING\nRequesting location, motion monitoring still on"

       ]

       STATE_IDLE [

         label="STATE_IDLE\nLocation and motion detection turned off\n"

             + "Significant motion monitoring still on"

       ]

       STATE_IDLE_MAINTENANCE [label="STATE_IDLE_MAINTENANCE\n"]

       STATE_ACTIVE -> STATE_INACTIVE [label="becomeInactiveIfAppropriateLocked()"]

       STATE_INACTIVE -> STATE_ACTIVE [

         label="handleMotionDetectedLocked(), becomeActiveLocked()"

       ]

       STATE_INACTIVE -> STATE_IDLE_PENDING [label="stepIdleStateLocked()"]

       STATE_IDLE_PENDING -> STATE_ACTIVE [

         label="handleMotionDetectedLocked(), becomeActiveLocked()"

       ]

       STATE_IDLE_PENDING -> STATE_SENSING [label="stepIdleStateLocked()"]

       STATE_SENSING -> STATE_ACTIVE [

         label="handleMotionDetectedLocked(), becomeActiveLocked()"

       ]

       STATE_SENSING -> STATE_LOCATING [label="stepIdleStateLocked()"]

       STATE_SENSING -> STATE_IDLE [

         label="stepIdleStateLocked()\n"

             + "No Location Manager OR (no Network provider AND no GPS provider)"

       ]

       STATE_LOCATING -> STATE_ACTIVE [

         label="handleMotionDetectedLocked(), becomeActiveLocked()"

       ]

       STATE_LOCATING -> STATE_IDLE [label="stepIdleStateLocked()"]

       STATE_IDLE -> STATE_ACTIVE [label="handleMotionDetectedLocked(), becomeActiveLocked()"]

       STATE_IDLE -> STATE_IDLE_MAINTENANCE [label="stepIdleStateLocked()"]

       STATE_IDLE_MAINTENANCE -> STATE_ACTIVE [

         label="handleMotionDetectedLocked(), becomeActiveLocked()"

       ]

       STATE_IDLE_MAINTENANCE -> STATE_IDLE [

         label="stepIdleStateLocked(), exitMaintenanceEarlyIfNeededLocked()"

       ]

     }

     subgraph light {

       label="light"

       LIGHT_STATE_ACTIVE [

         label="LIGHT_STATE_ACTIVE\nScreen on OR Charging OR Alarm going off soon"

       ]

       LIGHT_STATE_INACTIVE [label="LIGHT_STATE_INACTIVE\nScreen off AND Not charging"]

       LIGHT_STATE_PRE_IDLE [

         label="LIGHT_STATE_PRE_IDLE\n"

             + "Delay going into LIGHT_STATE_IDLE due to some running jobs or alarms"

       ]

       LIGHT_STATE_IDLE [label="LIGHT_STATE_IDLE\n"]

       LIGHT_STATE_WAITING_FOR_NETWORK [

         label="LIGHT_STATE_WAITING_FOR_NETWORK\n"

             + "Coming out of LIGHT_STATE_IDLE, waiting for network"

       ]

       LIGHT_STATE_IDLE_MAINTENANCE [label="LIGHT_STATE_IDLE_MAINTENANCE\n"]

       LIGHT_STATE_OVERRIDE [

         label="LIGHT_STATE_OVERRIDE\nDevice in deep doze, light no longer changing states"

       ]

       LIGHT_STATE_ACTIVE -> LIGHT_STATE_INACTIVE [

         label="becomeInactiveIfAppropriateLocked()"

       ]

       LIGHT_STATE_ACTIVE -> LIGHT_STATE_OVERRIDE [label="deep goes to STATE_IDLE"]

       LIGHT_STATE_INACTIVE -> LIGHT_STATE_ACTIVE [label="becomeActiveLocked()"]

       LIGHT_STATE_INACTIVE -> LIGHT_STATE_PRE_IDLE [label="active jobs"]

       LIGHT_STATE_INACTIVE -> LIGHT_STATE_IDLE [label="no active jobs"]

       LIGHT_STATE_INACTIVE -> LIGHT_STATE_OVERRIDE [label="deep goes to STATE_IDLE"]

       LIGHT_STATE_PRE_IDLE -> LIGHT_STATE_ACTIVE [label="becomeActiveLocked()"]

       LIGHT_STATE_PRE_IDLE -> LIGHT_STATE_IDLE [

         label="stepLightIdleStateLocked(), exitMaintenanceEarlyIfNeededLocked()"

       ]

       LIGHT_STATE_PRE_IDLE -> LIGHT_STATE_OVERRIDE [label="deep goes to STATE_IDLE"]

       LIGHT_STATE_IDLE -> LIGHT_STATE_ACTIVE [label="becomeActiveLocked()"]

       LIGHT_STATE_IDLE -> LIGHT_STATE_WAITING_FOR_NETWORK [label="no network"]

       LIGHT_STATE_IDLE -> LIGHT_STATE_IDLE_MAINTENANCE

       LIGHT_STATE_IDLE -> LIGHT_STATE_OVERRIDE [label="deep goes to STATE_IDLE"]

       LIGHT_STATE_WAITING_FOR_NETWORK -> LIGHT_STATE_ACTIVE [label="becomeActiveLocked()"]

       LIGHT_STATE_WAITING_FOR_NETWORK -> LIGHT_STATE_IDLE_MAINTENANCE

       LIGHT_STATE_WAITING_FOR_NETWORK -> LIGHT_STATE_OVERRIDE [

         label="deep goes to STATE_IDLE"

       ]

       LIGHT_STATE_IDLE_MAINTENANCE -> LIGHT_STATE_ACTIVE [label="becomeActiveLocked()"]

       LIGHT_STATE_IDLE_MAINTENANCE -> LIGHT_STATE_IDLE [

         label="stepLightIdleStateLocked(), exitMaintenanceEarlyIfNeededLocked()"

       ]

       LIGHT_STATE_IDLE_MAINTENANCE -> LIGHT_STATE_OVERRIDE [label="deep goes to STATE_IDLE"]

       LIGHT_STATE_OVERRIDE -> LIGHT_STATE_ACTIVE [

         label="handleMotionDetectedLocked(), becomeActiveLocked()"

       ]

     }

   }

 */

public class DeviceIdleController extends SystemService

        implements AnyMotionDetector.DeviceIdleCallback {