Fix DataView constructor and byte accessors.

lib/dom/templates/html/frog/factoryprovider_DataView.darttemplate

+// 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.
+
+class $FACTORYPROVIDER {
+  factory DataView(ArrayBuffer buffer,
+                   [int byteOffset = null, int byteLength = null])
+      native '''
+          if (byteOffset == null) return new DataView(buffer);
+          if (byteLength == null) return new DataView(buffer, byteOffset);
+          return new DataView(buffer, byteOffset, byteLength);
+      ''';
+}