Fixing Indexed DB supported check.

sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart

 library dart.dom.indexed_db;
 
 import 'dart:async';
 import 'dart:html';
 import 'dart:html_common';
 import 'dart:_js_helper' show Creates, Returns, JSName, Null;
 import 'dart:_foreign_helper' show JS;
 // 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.
@@ skipping 404 matching lines @@
       return _completeRequest(request);
     } catch (e, stacktrace) {
       return new Future.immediateError(e, stacktrace);
     }
   }
 
   /**
    * Checks to see if getDatabaseNames is supported by the current platform.
    */
   bool get supportsDatabaseNames {
-    return JS('bool', '!!(#.getDatabaseNames || #.webkitGetDatabaseNames)',
-        this, this);
+    return supported && JS('bool',
+        '!!(#.getDatabaseNames || #.webkitGetDatabaseNames)', this, this);
   }
 
 
   @DomName('IDBFactory.cmp')
   @DocsEditable
   int cmp(Object first, Object second) native;
 
   @JSName('deleteDatabase')
   @DomName('IDBFactory.deleteDatabase')
   @DocsEditable
@@ skipping 801 matching lines @@
 }
 // 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.
 
 
 @DocsEditable
 @DomName('IDBAny')
 class _IDBAny native "*IDBAny" {
 }