base

Fix app shelf being out of date after orientation change

* Share the data model for the two instances of the app shelf
  view (navbar has separate views for portrait and landscape).
* Synchronize the view to the data model on orientation change.
* Trigger the initial icon load from NavigationBarView.reorient()
  so it only happens once on startup.

Bug: 22383768
Change-Id: I37f1cbbdd7eccd02979f89770ade8251f1dc2e84