Add Supported class to dart:html

tools/dom/src/dartium_Platform.dart

Index: tools/dom/src/dartium_Platform.dart
diff --git a/editor/tools/plugins/com.google.dart.tools.debug.core_test/data/scripts/test.dart b/tools/dom/src/dartium_Platform.dart
similarity index 75%
copy from editor/tools/plugins/com.google.dart.tools.debug.core_test/data/scripts/test.dart
copy to tools/dom/src/dartium_Platform.dart
index e67e24b968af7775f7d780650dfb1819df5c754f..1db313dca8b04f67137e1dd7bc5eb6ba4bfbae3e 100644
--- a/editor/tools/plugins/com.google.dart.tools.debug.core_test/data/scripts/test.dart
+++ b/tools/dom/src/dartium_Platform.dart
@@ -2,8 +2,8 @@
 // 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 main() {
-  print("1");
-  print("2");
-  print("3");
+part of html;
+
+class Platform {
+  static final supportsTypedData = true;
 }