<!DOCTYPE html>
<html>
<head>
  <script>
    // Notify parent of our final URI:
    window.parent.postMessage(window.location.href, "*");
  </script>
  <style>
    html, body {
      margin: 0;
      height: 100%;
    }
    svg {
      display: block;
      height: 100%;
    }
  </style>
</head>
<body>
  <svg xmlns="http://www.w3.org/2000/svg"
       xmlns:xlink="http://www.w3.org/1999/xlink"
       version="1.1">
    <defs>
      <rect id="limeRect" width="100%" height="100%" fill="lime"/>
    </defs>
    <rect width="100%" height="100%" fill="red"/>
    <use xlink:href="#limeRect"/>
  </svg>
</body>
</html>
