I did advise Eric to start with just a straight DOM implementation, in order to manage the scope of this CL. Polymer has a bit of a learning curve, and I thought it would make this (larger) CL more approachable to take that out of the equation.

@umop, can you file an issue to convert the outline view over to a polymer element? And @ussuri, if you could add a rough outline of what the conversion process would be, or what the end result might look like, that would be great.