Ensure that newly-constructed elements don't have parents.

client/tests/client/html/SVGElementTests.dart

Index: client/tests/client/html/SVGElementTests.dart
diff --git a/client/tests/client/html/SVGElementTests.dart b/client/tests/client/html/SVGElementTests.dart
index 64adfea101029d590c86f4988e32e71038ad7489..275f328688b760b8caf857f0cd9000f9a49f9c73 100644
--- a/client/tests/client/html/SVGElementTests.dart
+++ b/client/tests/client/html/SVGElementTests.dart
@@ -39,6 +39,9 @@ void testSVGElement() {
         Expect.equals(svg, el.outerHTML);
       });
 
+      test('has no parent', () =>
+        Expect.isNull(new SVGElement.svg('<circle/>').parent));
+
       test('empty', () {
         Expect.throws(() => new SVGElement.svg(""),
             (e) => e is IllegalArgumentException);