Updating Element.scrollIntoView to be platform independent.

tests/html/element_test.dart

Index: tests/html/element_test.dart
diff --git a/tests/html/element_test.dart b/tests/html/element_test.dart
index 981db6d26224e4c4a49c65aa1abcf40270f5ced1..a1df4a424228e1bd773ea29a4b471038f8f5f9a1 100644
--- a/tests/html/element_test.dart
+++ b/tests/html/element_test.dart
@@ -618,6 +618,30 @@ main() {
     testUnsupported('removeLast', () => getQueryAll().removeLast());
   });
 
+  group('functional', () {
+    test('scrollIntoView', () {
+      var child = new DivElement();
+      document.body.append(child);
+      child.style.height = '10px';
+      child.style.marginTop = '200px';
+
+      expect(() {
+        child.scrollIntoView(alignCenter: true, alignTop: true);
+      }, throws);
+      expect(() {
+        child.scrollIntoView(alignCenter: true, alignBottom: true);
+      }, throws);
+      expect(() {
+        child.scrollIntoView(alignTop: true, alignBottom: true);
+      }, throws);
+
+      child.scrollIntoView(alignTop: true);
+      child.scrollIntoView(alignCenter: true);
+      child.scrollIntoView(alignBottom: true);
+      child.scrollIntoView();
+    });
+  });
+
   group('_ElementList', () {
     List<Element> makeElList() => makeElementWithChildren().children;