diff -r 000000000000 -r 6474c204b198 dom/workers/test/test_xhr_parameters.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/workers/test/test_xhr_parameters.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,75 @@
+function ok(what, msg) {
+  postMessage({ event: msg, test: 'ok', a: what });
+}
+
+function is(a, b, msg) {
+  postMessage({ event: msg, test: 'is', a: a, b: b });
+}
+
+// This is a copy of content/base/test/test_XHR_parameters.js
+var validParameters = [
+  undefined,
+  null,
+  {},
+  {mozSystem: ""},
+  {mozSystem: 0},
+  {mozAnon: 1},
+  {mozAnon: []},
+  {get mozAnon() { return true; }},
+  0,
+  7,
+  Math.PI,
+  "string",
+  true,
+  false,
+];
+
+var invalidParameters = [
+  {get mozSystem() { throw "Bla"; } },
+];
+
+
+function testParameters(havePrivileges) {
+
+  function testValidParameter(value) {
+    var xhr;
+    try {
+      xhr = new XMLHttpRequest(value);
+    } catch (ex) {
+      ok(false, "Got unexpected exception: " + ex);
+      return;
+    }
+    ok(!!xhr, "passed " + JSON.stringify(value));
+
+    // If the page doesnt have privileges to create a system or anon XHR,
+    // these flags will always be false no matter what is passed.
+    var expectedAnon = false;
+    var expectedSystem = false;
+    if (havePrivileges) {
+      expectedAnon = Boolean(value && value.mozAnon);
+      expectedSystem = Boolean(value && value.mozSystem);
+    }
+    is(xhr.mozAnon, expectedAnon, "testing mozAnon");
+    is(xhr.mozSystem, expectedSystem, "testing mozSystem");
+  }
+
+
+  function testInvalidParameter(value) {
+    try {
+      new XMLHttpRequest(value);
+      ok(false, "invalid parameter did not cause exception: " +
+         JSON.stringify(value));
+    } catch (ex) {
+      ok(true, "invalid parameter raised exception as expected: " +
+       JSON.stringify(ex));
+    }
+  }
+
+  validParameters.forEach(testValidParameter);
+  invalidParameters.forEach(testInvalidParameter);
+}
+
+self.onmessage = function onmessage(event) {
+  testParameters(event.data);
+  postMessage({test: "finish"});
+};