Tests resources initiator for images initiated by IMG tag, static CSS, CSS class added from JavaScript and XHR.

http://127.0.0.1:8000/devtools/network/resources/initiator.css: parser
    http://127.0.0.1:8000/devtools/network/resources/network-initiator-frame.html 2 60
http://127.0.0.1:8000/devtools/network/resources/resource.php?type=image&random=1&size=100: parser
    http://127.0.0.1:8000/devtools/network/resources/network-initiator-frame.html 4 53
http://127.0.0.1:8000/devtools/network/resources/resource.php?type=image&random=1&size=200: parser
    http://127.0.0.1:8000/devtools/network/resources/initiator.css undefined undefined
size=300 NOT FOUND
http://127.0.0.1:8000/devtools/network/resources/resource.php?type=image&random=1&size=400: script
    loadData http://127.0.0.1:8000/devtools/network/resources/network-initiator-frame.html 13 8
http://127.0.0.1:8000/devtools/network/resources/style.css: parser
    http://127.0.0.1:8000/devtools/network/resources/network-initiator-frame.html 8 35
http://127.0.0.1:8000/devtools/network/resources/empty.html: parser
    http://127.0.0.1:8000/devtools/network/resources/network-initiator-frame.html 17 45
http://127.0.0.1:8000/devtools/network/resources/module1.js: script
    http://127.0.0.1:8000/devtools/network/resources/network-initiator-frame.html 19 16
http://127.0.0.1:8000/devtools/network/resources/module2.js: script
    http://127.0.0.1:8000/devtools/network/resources/module1.js 2 20
http://127.0.0.1:8000/devtools/network/resources/example.ttf: parser
    http://127.0.0.1:8000/devtools/network/resources/initiator.css undefined undefined