title: control.registerOnChange is not a function
body: <p>I'm building a custom address component. I'm using it in a component:</p>
  
  <p>consumer.component.html:</p>
  
  <pre><code>&lt;form [formGroup]="form"&gt;
    &lt;nt-address [parent]="form" fG="addrGrp" formControlName="addrGrp"&gt;&lt;/nt-address&gt;
    {{form.value | json}}
  &lt;/form&gt;
  </code></pre>
  
  <p>consumer.component.ts</p>
  
  <pre><code>data = {
   addr1: 'Sample Address Line 1'
  };
  ngOnInit() {
    this.form = this.fb.group({
      addrGrp: this.fb.group(this.data)
    })
  }
  </code></pre>
  
  <p>nt-address.component.html:</p>
  
  <pre><code>&lt;div [formGroup]="parent"&gt;
     &lt;div [formGroupName]="fG"&gt;
       &lt;md-input-container&gt;
         &lt;input mdInput type="text" formControlName="addr1" placeholder="Address Line 1"&gt;
       &lt;/md-input-container&gt;
     &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>nt-address.component.ts:</p>
  
  <pre><code>export class AddressComponent extends ValueAccessorBase&lt;any&gt; {
     @Input() parent: FormGroup;
     @Input() fG: FormGroup;
  
  }
  </code></pre>
  
  <p>I'm getting this error:</p>
  
  <blockquote>
    <p>TypeError: control.registerOnChange is not a function</p>
  </blockquote>