title: Angular2 Renderer setElementStyle is not working
body: <p>This is my component metadata:</p>
  
  <pre><code>@Component({
     moduleId: module.id,
     selector: 'si-attribute-directive',
     template: `
        &lt;div myHighlight [customColor]="'red'"&gt;Highlight Me..&lt;/div&gt;
        &lt;br&gt;
        &lt;div myHighlight&gt;Highlight Me Too..&lt;/div&gt;
     `,
     directives: [MyHighlightDirective]
  })
  </code></pre>
  
  <p>And this is my directive:</p>
  
  <pre><code>import { Directive, ElementRef, OnInit, Renderer, Input } from '@angular/core';
  
  @Directive({
      selector: '[myHighlight]'
  })
  export class MyHighlightDirective implements OnInit {
     private _defaultColor : string = "green";
     @Input() customColor:string;
     constructor(private _elRef:ElementRef, private _renderer:Renderer) { }
  
     ngOnInit():any {
         this._renderer.setElementStyle(this._elRef, 'background-color', this.customColor || this._defaultColor);
     }
  }
  </code></pre>
  
  <p>It's getting the error: "Cannot set property 'background-color' of undefined".</p>