Refactor ConstantSystem

tests/compiler/dart2js/mock_libraries.dart

Index: tests/compiler/dart2js/mock_libraries.dart
diff --git a/tests/compiler/dart2js/mock_libraries.dart b/tests/compiler/dart2js/mock_libraries.dart
index c6506fde57ce907da54156ba0415bc141bd0d803..97ad29f90faec8eaf181c95d1f915c562822e3c1 100644
--- a/tests/compiler/dart2js/mock_libraries.dart
+++ b/tests/compiler/dart2js/mock_libraries.dart
@@ -98,7 +98,7 @@ const Map<String, String> DEFAULT_CORE_LIBRARY = const <String, String>{
   'Resource': 'class Resource {}',
   'StackTrace': 'abstract class StackTrace {}',
   'String': 'class String implements Pattern {}',
-  'Symbol': 'class Symbol { final name; const Symbol(this.name); }',
+  'Symbol': 'class Symbol { final _name; const Symbol(this._name); }',
   'Type': 'class Type {}',
   'Pattern': 'abstract class Pattern {}',
   '_genericNoSuchMethod': '_genericNoSuchMethod(a,b,c,d,e) {}',