title: ControlValueAccessor with multiple formControl in child component
body: <p>I have multiple formcontrols in the child component, how to apply validators in the child component, So that original form will become invalid. It would be ideal to implement it with ControlValueAccessor but want to start with simple @input form group. </p>
  
  <pre class="lang-js prettyprint-override"><code>@Component({
    selector: 'my-child',
    template: `
  
    &lt;h1&gt;Child&lt;/h1&gt;
    &lt;div [formGroup]="childForm"&gt;
      &lt;input formControlName="firstName"&gt;
      &lt;input formControlName="lastName"&gt;
    &lt;/div&gt;
    `
  })
  
  export class Child {
    @Input()
    childForm: FormGroup;
  }
  </code></pre>
  
  <p><a href="http://plnkr.co/edit/K1xAak4tlUKtZmOV1CAQ" rel="noreferrer">http://plnkr.co/edit/K1xAak4tlUKtZmOV1CAQ</a></p>