Support for map literals in cps js emitter

pkg/compiler/lib/src/js_backend/codegen/glue.dart

 // Copyright (c) 2014, 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 code_generator_dependencies;
 
 import '../js_backend.dart';
 import '../../dart2jslib.dart';
 import '../../js_emitter/js_emitter.dart';
 import '../../js/js.dart' as js;
@@ skipping 30 matching lines @@
   js.Expression elementAccess(Element element) {
     return _namer.elementAccess(element);
   }
 
   String safeVariableName(String name) {
     return _namer.safeVariableName(name);
   }
 
   ClassElement get listClass => _compiler.listClass;
 
+  ConstructorElement get mapLiteralConstructor {
+    return _backend.mapLiteralConstructor;
+  }
+
+  ConstructorElement get mapLiteralConstructorEmpty {
+    return _backend.mapLiteralConstructorEmpty;
+  }
+
   FunctionElement get identicalFunction => _compiler.identicalFunction;
 
   String invocationName(Selector selector) {
     return _namer.invocationName(selector);
   }
 
   bool isIntercepted(Selector selector) {
     return _backend.isInterceptedSelector(selector);
   }
 
 }