Import //fetch from Web Platform Tests.

third_party/WebKit/LayoutTests/external/wpt/fetch/nosniff/script.html

+<script src=/resources/testharness.js></script>
+<script src=/resources/testharnessreport.js></script>
+<div id=log></div>
+<script>
+  var log = function() {}, // see comment below
+      p = function() {}, // see comment below
+      fails = ["", "?type=", "?type=x", "?type=x/x"],
+      passes = ["?type=text/javascript", "?type=text/ecmascript", "?type=text/ecmascript;blah"]
+
+  // Ideally we'd also check whether the scripts in fact execute, but that would involve
+  // timers and might get a bit racy without cross-browser support for the execute events.
+
+  fails.forEach(function(urlpart) {
+    async_test(function(t) {
+      var script = document.createElement("script")
+      script.onerror = t.step_func_done(function(){})
+      script.onload = t.unreached_func("Unexpected load event")
+      script.src = "resources/js.py" + urlpart
+      document.body.appendChild(script)
+    }, "URL query: " + urlpart)
+  })
+
+  passes.forEach(function(urlpart) {
+    async_test(function(t) {
+      var script = document.createElement("script")
+      script.onerror = t.unreached_func("Unexpected error event")
+      script.onload = t.step_func_done(function(){})
+      script.src = "resources/js.py" + urlpart + "&outcome=p"
+      document.body.appendChild(script)
+    }, "URL query: " + urlpart)
+  })
+</script>