Support SVGElement#elements, #innerHTML, and #outerHTML. Also add a .svg constructor.

client/tests/client/html/html_tests.dart

Index: client/tests/client/html/html_tests.dart
diff --git a/client/tests/client/html/html_tests.dart b/client/tests/client/html/html_tests.dart
index 17faef024744ac8a5892640aba2c52d11ec68396..ac67a90906031bbc046c9c84325c04832f55a3ad 100644
--- a/client/tests/client/html/html_tests.dart
+++ b/client/tests/client/html/html_tests.dart
@@ -15,6 +15,7 @@
 #source('ElementTests.dart');
 #source('EventTests.dart');
 #source('MeasurementTests.dart');
+#source('SVGElementTests.dart');
 
 main() {
   group('CSSStyleDeclaration', testCSSStyleDeclaration);
@@ -22,4 +23,5 @@ main() {
   group('Element', testElement);
   group('Event', testEvents);
   group('Measurement', testMeasurement);
+  group('SVGElement', testSVGElement);
 }