Support map and list literals in analyzer2dart.

sdk/lib/_internal/compiler/implementation/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 'elements.dart';
 import '../constants/expressions.dart';
 import '../helpers/helpers.dart';  // Included for debug helpers.
 import '../tree/tree.dart';
@@ skipping 1213 matching lines @@
 class LocalVariableElementX extends VariableElementX
     implements LocalVariableElement {
   LocalVariableElementX(String name,
                         ExecutableElement enclosingElement,
                         VariableList variables,
                         Token token)
       : super(name, ElementKind.VARIABLE, enclosingElement, variables, token) {
     createDefinitions(variables.definitions);
   }
 
-  // TODO(johnniwinther): Remove this when the dart `backend_ast` does not need
-  // [Element] for entities.
-  LocalVariableElementX.synthetic(String name,
-                                  ExecutableElement enclosingElement,
-                                  VariableList variables)
-      : super(name, ElementKind.VARIABLE, enclosingElement, variables, null);
-
   ExecutableElement get executableContext => enclosingElement;
 
   ExecutableElement get memberContext => executableContext.memberContext;
 
   bool get isLocal => true;
 }
 
 class FieldElementX extends VariableElementX
     with AnalyzableElementX implements FieldElement {
   List<FunctionElement> nestedClosures = new List<FunctionElement>();
@@ skipping 1465 matching lines @@
   AstElement get definingElement;
 
   bool get hasResolvedAst => definingElement.hasTreeElements;
 
   ResolvedAst get resolvedAst {
     return new ResolvedAst(declaration,
         definingElement.node, definingElement.treeElements);
   }
 
 }