Only have one method for generating a method.

dart/sdk/lib/_internal/compiler/implementation/js_emitter/class_builder.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.
 
 part of dart2js.js_emitter;
 
 /**
  * A data structure for collecting fragments of a class definition.
  */
 class ClassBuilder {
   final List<jsAst.Property> properties = <jsAst.Property>[];
 
   /// Set to true by user if class is indistinguishable from its superclass.
   bool isTrivial = false;
 
   // Has the same signature as [DefineStubFunction].
   void addProperty(String name, jsAst.Expression value) {
     properties.add(new jsAst.Property(js.string(name), value));
   }
 
   jsAst.Expression toObjectInitializer() {
     return new jsAst.ObjectInitializer(properties);
   }
+
+  /// This method is temporary. Do not use it unless you're working on
+  /// transforming code to build jsAst.Nodes.
+  void writeOn_DO_NOT_USE(CodeBuffer buffer,
+                          Compiler compiler,
+                          String separatedBy) {
+    for (jsAst.Property property in properties) {
+      if (!buffer.isEmpty) buffer.write(separatedBy);
+      buffer.write(jsAst.prettyPrint(property, compiler));
+    }
+  }
 }