Right now there is currently a LocationBarViewController that is unused by the toolbar.  LocationBarCoordinator should updated to manage a child view controller for the toolbar views.  Integrating LocationBarViewController will allow accurate signals for when the location bar UI is visible, which can then be used to set up the named layout guides for the keyboard accessory view (note: named layout guides aren't accessible from the location bar until it's added to BVC's window).

The initial pass at this bug will implement LocationBarViewController as a simple wrapper around LocationBarView.