implement LabeledStatement and Break in kernel

pkg/compiler/lib/src/elements/modelx.dart

 // Copyright (c) 2013, 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.modelx;
 
 import '../common.dart';
 import '../common/names.dart' show Identifiers;
 import '../common/resolution.dart' show Resolution, ParsingContext;
 import '../compiler.dart' show Compiler;
@@ skipping 3191 matching lines @@
 
   bool get isTarget => isBreakTarget || isContinueTarget;
 
   String toString() => 'Label:${name}';
 }
 
 class JumpTargetX implements JumpTarget {
   final ExecutableElement executableContext;
   final Node statement;
   final int nestingLevel;
-  Link<LabelDefinition> labels = const Link<LabelDefinition>();
+  List<LabelDefinition> labels = <LabelDefinition>[];
   bool isBreakTarget = false;
   bool isContinueTarget = false;
 
   final int hashCode = ElementX.newHashCode();
 
   JumpTargetX(this.statement, this.nestingLevel, this.executableContext);
 
   String get name => "target";
 
   bool get isTarget => isBreakTarget || isContinueTarget;
 
   LabelDefinition addLabel(Label label, String labelName) {
     LabelDefinition result = new LabelDefinitionX(label, labelName, this);
-    labels = labels.prepend(result);

[Siggi Cherem (dart-lang), 2016/12/17 00:43:16]

It seems the order after this change will be reversed. I'm guessing that doesn't
matter in this case, but just double checking?

[Harry Terkelsen, 2016/12/17 00:50:36]

The order doesn't matter because they are all labels on the same target.

+    labels.add(result);
     return result;
   }
 
   bool get isSwitch => statement is SwitchStatement;
 
   String toString() => 'Target:$statement';
 }
 
 class TypeVariableElementX extends ElementX
     with AstElementMixin
@@ skipping 177 matching lines @@
       body = node.asFunctionExpression().body;
     }
     return new ParsedResolvedAst(
         declaration,
         node,
         body,
         definingElement.treeElements,
         definingElement.compilationUnit.script.resourceUri);
   }
 }