The directiveIntrospector was a bit of a hack to allow the router to
read the `$routeConfig` annocation and `$routerCanActivate` hook from
directives when they were registered.
It turns out that if we put these properties on the component controller's
constructor function (i.e. as static class methods) then we can simply
use the `$injector` to access it as required.
Currently, people put the properties directly on their component definition
objects. In Angular 1.5.1, we will copy these properties onto the controller
constructor to maintain a simple migration path. But going forward it may be
better to encourage people to add the properties directly to the controller
constructor.
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