implement LabeledStatement and Break in kernel

pkg/compiler/lib/src/elements/elements.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 elements;
 
 import '../common.dart';
 import '../common/resolution.dart' show Resolution;
 import '../compiler.dart' show Compiler;
 import '../constants/constructors.dart';
@@ skipping 1646 matching lines @@
 
   void setBreakTarget();
   void setContinueTarget();
 }
 
 /// A jump target is the reference point of a statement or switch-case,
 /// either by label or as the default target of a break or continue.
 abstract class JumpTarget extends Local {
   Node get statement;
   int get nestingLevel;
-  Link<LabelDefinition> get labels;
+  List<LabelDefinition> get labels;
 
   bool get isTarget;
   bool get isBreakTarget;
   bool get isContinueTarget;
   bool get isSwitch;
 
   // TODO(kasperl): Try to get rid of these.
   void set isBreakTarget(bool value);
   void set isContinueTarget(bool value);
 
@@ skipping 256 matching lines @@
   /// by a field.
   bool get isDeclaredByField;
 
   /// Returns `true` if this member is abstract.
   bool get isAbstract;
 
   /// If abstract, [implementation] points to the overridden concrete member,
   /// if any. Otherwise [implementation] points to the member itself.
   Member get implementation;
 }