fixes #40, extension methods for primitive types

test/generated_sdk/lib/core/core.dart

Index: test/generated_sdk/lib/core/core.dart
diff --git a/test/generated_sdk/lib/core/core.dart b/test/generated_sdk/lib/core/core.dart
index 71d53fc3d238e721c7c87f3f9262b942108a2ece..01253b3f11e6da499054093bcfb7a9dcdde0b994 100644
--- a/test/generated_sdk/lib/core/core.dart
+++ b/test/generated_sdk/lib/core/core.dart
@@ -203,18 +203,4 @@ 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);