Tests XHR network resource type and content for asynchronous requests. Bug 61205
http://127.0.0.1:8000/devtools/network/resources/resource.php
resource.type: xhr
resource.content after requesting content: Hello world
VM:5 XHR loaded: 1
Tests XHR network resource type and content for asynchronous requests. Bug 61205
http://127.0.0.1:8000/devtools/network/resources/resource.php
resource.type: xhr
resource.content after requesting content: Hello world
VM:5 XHR loaded: 1