third_party/WebKit/LayoutTests/fast/dom/shadow/shadowdom-for-embed-with-content.html - chromium/src - Git at Google

 <!DOCTYPE html>
 <body>
 <embed src="non-existent.swf">
 <!-- EMBED elements can't have children. -->
 </embed>

 <script>
 document.querySelector('embed').createShadowRoot().innerHTML = 'Get Flash Player. <content select="*">Or Shockwave Player?</content>';
 </script>
 </body>
	<!DOCTYPE html>
	<body>
	<embed src="non-existent.swf">
	<!-- EMBED elements can't have children. -->
	</embed>

	<script>
	document.querySelector('embed').createShadowRoot().innerHTML = 'Get Flash Player. <content select="*">Or Shockwave Player?</content>';
	</script>
	</body>