Fade out the mouse pointer after inactivity or other events.

Fades out the mouse pointer:
- after 15 seconds of inactivity normally
- after 3 seconds of inactivity in lights out mode
- after a non-modifier key down
- after a touch down

Extended the native Looper to support enqueuing time delayed
messages.  This is used by the PointerController to control
pointer fade timing.

Change-Id: I87792fea7dbe2d9376c78cf354fe3189a484d9da
diff --git a/native/include/android/looper.h b/native/include/android/looper.h
index a9d8426..24e3967 100644
--- a/native/include/android/looper.h
+++ b/native/include/android/looper.h
@@ -148,7 +148,8 @@
 
 /**
  * For callback-based event loops, this is the prototype of the function
- * that is called.  It is given the file descriptor it is associated with,
+ * that is called when a file descriptor event occurs.
+ * It is given the file descriptor it is associated with,
  * a bitmask of the poll events that were triggered (typically ALOOPER_EVENT_INPUT),
  * and the data pointer that was originally supplied.
  *