<html>
<head>
<script>
function boom()
{
  var canvas = document.getElementById("canvas");
  var ctx = SpecialPowers.wrap(canvas.getContext("2d"));
  ctx.drawWindow(window, 0, 0, canvas.width, canvas.height, "red");
}
</script>
</head>
<body onload="boom();">
<canvas id="canvas" width="10" height="10"></canvas>
</body>
</html>
