title: JS ClipboardEvent clipboardData always empty
body: <p>I want to recieve files via CTRL+V from the ClipboardEvent in Angular6.
  But the clipboardData is always empty (I tested images and text).
  I tested it on the latest Chrome/Firefox release.</p>
  
  <p><a href="https://i.stack.imgur.com/ZsOCa.png" rel="noreferrer"><img src="https://i.stack.imgur.com/ZsOCa.png" alt="enter image description here"></a></p>
  
  <p>As you can see on the screenshot, the files/items attribute is empty.
  This is my current code:</p>
  
  <pre><code>  ngOnInit() {
      document.addEventListener('paste', this.pasteEvent);
    }
  
    private pasteEvent(e): void {
      console.log(e);
    }
  </code></pre>