title: How to call an action on the app route from any component without having to pass it everywhere?
body: <p>I'd like to be able to open a login modal from any component without having to pass it through the component hierarchy each time I need it.</p>
  
  <p>The openModal action on the application is the same as in the modal cookbook in the guides :</p>
  
  <pre><code>App.ApplicationRoute = Ember.Route.extend({
    actions: {
      openModal: function(modalName) {
        return this.render(modalName, {
          into: 'application',
          outlet: 'modal'
        });
      }
    }
  });
  </code></pre>
  
  <p>I would like to avoid :</p>
  
  <pre><code>{{my-component openModal="openModal" otherArgs=args ... }}
  </code></pre>
  
  <p>Plus
      import Ember from 'ember';</p>
  
  <pre><code>export default Ember.Component.extend({
    actions: {
      openModal(modalName) {
        this.sendAction('openModal', modalName);
      }
    }
  });
  </code></pre>
  
  <p>I could use a service injected in each component, but then how to call the openModal action on the application route from the service ?</p>
  
  <p>Thanks !</p>