Fix identity and SVGAnimatedString issues with element_classes_test

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index 17670110796e83861a25168051868d668922a254..cf086726fbe8103271194eea8f1122d2e7265bf7 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -13120,8 +13120,9 @@ abstract class Element extends Node implements GlobalEventHandlers, ParentNode,
     // offsetParent, "tops out" at BODY. But people could conceivably pass in
     // the document.documentElement and I want it to return an absolute offset,
     // so we have the special case checking for HTML.
-    bool foundAsParent = identical(current, parent) || parent.tagName == 'HTML';
-    if (current == null || identical(current, parent)) {
+    bool sameAsParent = identical(current, parent);
+    bool foundAsParent = sameAsParent || parent.tagName == 'HTML';
+    if (current == null || sameAsParent) {
       if (foundAsParent) return new Point(0, 0);
       throw new ArgumentError("Specified element is not a transitive offset "
           "parent of this element.");