Making supressed DOM types abstract

sdk/lib/web_sql/dart2js/web_sql_dart2js.dart

Index: sdk/lib/web_sql/dart2js/web_sql_dart2js.dart
diff --git a/sdk/lib/web_sql/dart2js/web_sql_dart2js.dart b/sdk/lib/web_sql/dart2js/web_sql_dart2js.dart
index 596ef4b82d4ce13442d8c2dd55f7bcfc73affb33..649b86180882900dccaef95f23c65788757b1f4a 100644
--- a/sdk/lib/web_sql/dart2js/web_sql_dart2js.dart
+++ b/sdk/lib/web_sql/dart2js/web_sql_dart2js.dart
@@ -445,7 +445,7 @@ class SqlTransaction native "*SQLTransaction" {
 @SupportedBrowser(SupportedBrowser.CHROME)
 @SupportedBrowser(SupportedBrowser.SAFARI)
 @Experimental
-class _DatabaseSync native "*DatabaseSync" {
+abstract class _DatabaseSync native "*DatabaseSync" {
 }
 // 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
@@ -457,5 +457,5 @@ class _DatabaseSync native "*DatabaseSync" {
 @SupportedBrowser(SupportedBrowser.CHROME)
 @SupportedBrowser(SupportedBrowser.SAFARI)
 @Experimental
-class _SQLTransactionSync native "*SQLTransactionSync" {
+abstract class _SQLTransactionSync native "*SQLTransactionSync" {
 }