Action changes:
* Include whether the user is logged in/out and information about the
current page in the BOOT action.
* Add the EVENT_LOGGED action, which represents the eventLoggined change
listener logging the queued event.
Reducer changes:
* Move all tokens and timing information from the preview reducer to the
eventLogging reducer.
* Make the eventLogging reducer reset the state.
Changes:
* Add the mw.popups.createSchema function, which constructs an instance
of the mw.eventLog.Schema object that can be used to log Popups
events.
* Add the eventLogging change listener, which logs the queued event.
* Add hand-crafted, artisanal documentation.
Bug: T152225
Change-Id: I8a3f58358b211cc55417dcda7e796fe538e3d910
