fixes #40, extension methods for primitive types

test/generated_sdk/lib/core/core.dart

 // 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.
 
 /**
  *
  * Built-in types, collections,
  * and other core functionality for every Dart program.
  *
  * This library is automatically imported.
@@ skipping 185 matching lines @@
 part "sink.dart";
 part "stacktrace.dart";
 part "stopwatch.dart";
 part "string.dart";
 part "string_buffer.dart";
 part "string_sink.dart";
 part "symbol.dart";
 part "type.dart";
 part "uri.dart";
 
-String _symbolToString(Symbol symbol) => _symbol_dev.Symbol.getName(symbol);
-_symbolMapToStringMap(Map<Symbol, dynamic> map) {
-  if (map == null) return null;
-  var result = new Map<String, dynamic>();
-  map.forEach((Symbol key, value) {
-    result[_symbolToString(key)] = value;
-  });
-  return result;
-}
-class SupportJsExtensionMethods {
-  const SupportJsExtensionMethods();
-}
-class _ListConstructorSentinel {
-  const _ListConstructorSentinel();
-}
+String _symbolToString(Symbol symbol) => _symbol_dev.Symbol.getName(symbol);