Quick step/scrub/switch logging

- state transition happening due to Home and back is handled by
  specifying src target as 'from' container and dst target as the 'to'
  container
- Source and Destination container shows FROM and TO state for SWIPE/FLING
- event.isStateChange = true indicates that an action resulted in
  state transition
- Elapsed container millis is the screen time on the source container

Bug: 70181187

- logcat printout with setprop log.tag.UserEvent VERBOSE
1) State: WORKSPACE -> ALLAPPS
  action:FLING direction=UP
  Source child:HOTSEAT id=0	parent:WORKSPACE id=0
  Destination child:ALLAPPS
  Elapsed container 1225 ms, session 1225 ms, action 0 ms

2) ALLAPPS -> HOMESCREEN
  action:FLING direction=DOWN
  Source child:ALLAPPS	parent:ALLAPPS
  Destination child:WORKSPACE id=0
  Elapsed container 971 ms, session 2197 ms, action 0 ms

3) HOMESCREEN -> OVERVIEW
  action:FLING direction=UP
  Source child:NAVBAR	parent:WORKSPACE id=0
  Destination child:TASKSWITCHER
  Elapsed container 4834 ms, session 4834 ms, action 0 ms

4) OVERVIEW-> ALLAPPS
  action:FLING direction=UP
  Source child:TASK	parent:TASKSWITCHER
  Destination child:ALLAPPS
  Elapsed container 2176 ms, session 7010 ms, action 0 ms

5) ALLAPPS->OVERVIEW
  action:FLING direction=DOWN
  Source child:ALLAPPS	parent:ALLAPPS
  Destination child:TASKSWITCHER
  Elapsed container 3683 ms, session 10693 ms, action 0 ms

6) OVERVIEW-> HOMESCREEN
  action:FLING direction=DOWN
  Source child:TASK	parent:TASKSWITCHER
  Destination child:WORKSPACE id=0
  Elapsed container 2108 ms, session 12801 ms, action 0 ms

7) APPS-> OVERVIEW
  action:FLING direction=UP
  Source child:NAVBAR	parent:APP
  Destination child:TASKSWITCHER
  Elapsed container 104 ms, session 104 ms, action 0 ms

8) Quickscrub: action:DRAGANDDROP Source child: QUICK

9) Quickswitch: action:FLING Source child: QUICK

Change-Id: I5898230859ff600f48a2a873a40b670fe4d39a0d