third_party/blink/web_tests/http/tests/security/mixedContent/resources/frame-with-insecure-css-image.html - chromium/src - Git at Google

 <!DOCTYPE html>
 <html>
 <head>
 <!-- External css file needed to trigger a css cache image load -->
 <link href="fetch-insecure-css-image.css" rel="stylesheet" type="text/css" />
 </head>
 <body>
 <img id="insecure-css-img">
 <script>
 window.addEventListener("load", function() {
     if (parent.window)
         parent.window.postMessage('done', '*');
 }, false);
 </script>
 </body>
 </html>
	<!DOCTYPE html>
	<html>
	<head>
	<!-- External css file needed to trigger a css cache image load -->
	<link href="fetch-insecure-css-image.css" rel="stylesheet" type="text/css" />
	</head>
	<body>
	<img id="insecure-css-img">
	<script>
	window.addEventListener("load", function() {
	if (parent.window)
	parent.window.postMessage('done', '*');
	}, false);
	</script>
	</body>
	</html>