Add a method to let a properly permissioned app directly

manipulate the user activity timeout.  We should come up
with a better API for this, but this is for a last minute
power manager hack to turn off the screen sooner after a
phone call ends.

Change-Id: I76422f952e3e894c90b3311e7d889899c79cbbaa

core/java/android/os/IPowerManager.aidl

@@ -26,6 +26,7 @@ interface IPowerManager
     void releaseWakeLock(IBinder lock, int flags);
     void userActivity(long when, boolean noChangeLights);
     void userActivityWithForce(long when, boolean noChangeLights, boolean force);
+    void clearUserActivityTimeout(long now, long timeout);
     void setPokeLock(int pokey, IBinder lock, String tag);
     int getSupportedWakeLockFlags();
     void setStayOnSetting(int val);