Add Supported class to dart:html

sdk/lib/html/dartium/html_dartium.dart

Index: sdk/lib/html/dartium/html_dartium.dart
diff --git a/sdk/lib/html/dartium/html_dartium.dart b/sdk/lib/html/dartium/html_dartium.dart
index dd0de2703be0f393892c19a89c9701644549ac19..24c115cc291e0095c8776d6e71b6d606e4751feb 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -522,9 +522,6 @@ class ArrayBuffer extends NativeFieldWrapperClass1 {
   @DocsEditable
   static ArrayBuffer _create(length) native "ArrayBuffer_constructorCallback";
 
-  /// Checks if this type is supported on the current platform.
-  static bool get supported => true;
-
   @DomName('ArrayBuffer.byteLength')
   @DocsEditable
   int get byteLength native "ArrayBuffer_byteLength_Getter";
@@ -33469,6 +33466,14 @@ class _TypedArrayFactoryProvider {
 class _TextFactoryProvider {
   static Text createText(String data) => document.$dom_createTextNode(data);
 }
+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// 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.
+
+
+class Platform {
+  static final supportsTypedData = true;
+}
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // 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.