For link generation to areas, we need to provide the set of values that
the route could potentially provide.
Basically if we know what action we want to reach, we want to know whether
or not a given route could hit that action before giving it the OK to
generate a link.
For instance a route like '{controller}' couldn't hit an action like
'HomeController:DoACoolThing', since it can never provide a value for
'action'. This makes it possible for WebFX to make the right decision
without changing the behavior of any of the routing constructs. This also
has the side-effect of removing a class of order dependencies in routing
that cause bad links to be generated.
Doug Bunting
Andrew Peters
Ryan Nowak
harshgMSFT