Serves as the base non-VE container for NgClass.
While this is a base class that NgClass extends from, the class itself acts as a container for non-VE code to setup a link to the
[class] host binding (via the static
ɵdir property on the class).
Note that the
ɵdir property's code is switched depending if VE is present or not (this allows for the binding code to be set only for newer versions of Angular).
| ||Declared in constructor.|