Fix up recently-landed test for async and target changes to postMessage. r=orange

content/xbl/test/file_bug379959_cross.html

@@ -17,9 +17,9 @@
 <script>
 onload = function() {
   nodes = document.getAnonymousNodes(document.getElementById('div1'));
-  parent.postMessage(nodes ? nodes.length : 0);
+  parent.postMessage(nodes ? nodes.length : 0, "http://localhost:8888");
   nodes = document.getAnonymousNodes(document.getElementById('div2'));
-  parent.postMessage(nodes ? nodes.length : 0);
+  parent.postMessage(nodes ? nodes.length : 0, "http://localhost:8888");
 }
 </script>
 </html>

content/xbl/test/file_bug379959_data.html

@@ -12,7 +12,7 @@
 <script>
 onload = function() {
   nodes = document.getAnonymousNodes(document.getElementById('d'));
-  parent.postMessage(nodes ? nodes.length : 0);
+  parent.postMessage(nodes ? nodes.length : 0, "http://localhost:8888");
 }
 </script>
 </html>

content/xbl/test/test_bug379959.html

@@ -27,9 +27,14 @@ SimpleTest.waitForExplicitFinish();
 gen = runTest();
 var messages = 0;
 
-document.addEventListener("message",
-                          function(e) { messages++; gen.send(e.data); },
-                          false);
+function receiveMessage(e)
+{
+  is(e.origin, "http://localhost:8888", "wrong sender!");
+  messages++;
+  gen.send(e.data);
+}
+
+window.addEventListener("message", receiveMessage, false);
 
 const prefName = "layout.debug.enable_data_xbl";