<!DOCTYPE html>
<html>
<head>
<style>
@font-face {
  font-family: "z";
  src: url(invalid);
}
</style>

<script>
function boom()
{
  var ctx = document.querySelector("canvas").getContext('2d');
  ctx.font = "10px serif";
  document.querySelector("style").appendChild(document.createTextNode(" "));
  ctx.measureText("123");
}
</script>
</head>

<body onload="boom();">
<canvas width="100" height="100"></canvas>
</body>
</html>
