Implement automatically generated constructors for frog and dartium dart:html

client/dom/templates/html/frog/factoryprovider_XMLHttpRequest.darttemplate

+
+class _XMLHttpRequestFactoryProvider {
+  factory XMLHttpRequest() native 'return new XMLHttpRequest();';
+
+  factory XMLHttpRequest.getTEMPNAME(String url,
+      onSuccess(XMLHttpRequest request)) {
+    final request = new XMLHttpRequest();
+    request.open('GET', url, true);
+
+    // TODO(terry): Validate after client login added if necessary to forward
+    //              cookies to server.
+    request.withCredentials = true;
+
+    // Status 0 is for local XHR request.
+    request.on.readyStateChange.add((e) {
+      if (request.readyState == XMLHttpRequest.DONE &&
+          (request.status == 200 || request.status == 0)) {
+        onSuccess(request);
+      }
+    });
+
+    request.send();
+
+    return request;
+  }
+}