Move these dart:html tests from Dartium layout test to client tests.

client/tests/client/html/XHRTests.dart

Index: client/tests/client/html/XHRTests.dart
diff --git a/client/tests/client/html/XHRTests.dart b/client/tests/client/html/XHRTests.dart
new file mode 100644
index 0000000000000000000000000000000000000000..be489787e97b6d22885ff3725875a55dd8300690
--- /dev/null
+++ b/client/tests/client/html/XHRTests.dart
@@ -0,0 +1,20 @@
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+
+void testXHR() {
+  print(window.location.href);
+  asyncTest('XHR', 1, () {
+    XMLHttpRequest xhr = new XMLHttpRequest();
+    xhr.open("GET", "NonExistingFile", true);
+    xhr.on.readyStateChange.add((event) {
+        if (xhr.readyState == 4) {
+          Expect.equals(0, xhr.status);
+          Expect.stringEquals('', xhr.responseText);
+          callbackDone();
+        }
+      });
+    xhr.send();
+  });
+}