Tests XSL stylsheet content. http://crbug.com/603806

http://127.0.0.1:8000/devtools/network/resources/xml-with-stylesheet.xml
resource.type: document
resource.content: <?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="xml-with-stylesheet.xsl"?>
<foo>
  <bar>someData</bar>
</foo>