Update ClosureScope.toString

pkg/compiler/lib/src/closure.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.
 
 library closureToClassMapper;
 
 import 'common.dart';
 import 'common/names.dart' show Identifiers;
 import 'common/resolution.dart' show ParsingContext, Resolution;
 import 'common/tasks.dart' show CompilerTask;
@@ skipping 363 matching lines @@
   bool isCapturedVariable(VariableElement variable) {
     return capturedVariables.containsKey(variable);
   }
 
   void forEachCapturedVariable(
       f(LocalVariableElement variable, BoxFieldElement boxField)) {
     capturedVariables.forEach(f);
   }
 
   String toString() {
+    String separator = '';
     StringBuffer sb = new StringBuffer();
+    sb.write('ClosureScope(');
     if (boxElement != null) {
       sb.write('box=$boxElement');
+      separator = ',';
     }
     if (boxedLoopVariables.isNotEmpty) {
-      if (sb.isNotEmpty) {
-        sb.write(',');
-      }
+      sb.write(separator);
       sb.write('boxedLoopVariables=${boxedLoopVariables}');
+      separator = ',';
     }
     if (capturedVariables.isNotEmpty) {
-      if (sb.isNotEmpty) {
-        sb.write(',');
-      }
-      sb.write('capturedVariables=');
-      capturedVariables.forEach((Local local, BoxFieldElement field) {
-        sb.write('$local->${field} ');
-      });
+      sb.write(separator);
+      sb.write('capturedVariables=$capturedVariables');
     }
+    sb.write(')');
     return sb.toString();
   }
 }
 
 class ClosureClassMap {
   // The closure's element before any translation. Will be null for methods.
   final LocalFunctionElement closureElement;
   // The closureClassElement will be null for methods that are not local
   // closures.
   final ClosureClassElement closureClassElement;
@@ skipping 756 matching lines @@
 ///
 /// Move the below classes to a JS model eventually.
 ///
 abstract class JSEntity implements Entity {
   Entity get declaredEntity;
 }
 
 abstract class PrivatelyNamedJSEntity implements JSEntity {
   Entity get rootOfScope;
 }