title: Can an Ember component observe a controller property?
body: <p>I have a controller and a component. when the component is rendered, it is passed on in this manner:</p>
  
  <pre><code>{{modal-filter feature=feature parentController=this.controller}}
  </code></pre>
  
  <p>where feature is a param passed in via controller to handlebars, and parentController is the controller. </p>
  
  <p>Now, in the controller itself, there is an property (an array). let's call that array requiredValues.</p>
  
  <p>Now within a controller/component itself, we can easily set:</p>
  
  <pre><code>valueObserver : function(){
       ...
  }.observes('requiredValues')
  </code></pre>
  
  <p>However, I need to observe this controller property from a the modal-filter component. So in the modal-filter component, what would I put as the observer function:</p>
  
  <pre><code>valueObserver : function(){
       ...
  }.observes(???)
  </code></pre>