anchor.diff:    void emitDeferredCode(CodeBuffer buffer) {
       if (buffer.isEmpty) return;
   
  -    if (needsDefineClass) {
  -      buffer.add('$finishClassesName(\$\$,'
  -                 '$_${namer.CURRENT_ISOLATE},'
  -                 '$_$isolatePropertiesName)$N');
  -      // Reset the map.
  -      buffer.add("\$\$$_=$_{}$N");
  -    }
  +    buffer.add(n);
   
       buffer.add('${namer.CURRENT_ISOLATE}$_=${_}old${namer.CURRENT_ISOLATE}$N');
   
  
positive.code:   final Namer namer;
    ConstantEmitter constantEmitter;
    NativeEmitter nativeEmitter;
    CodeBuffer boundClosureBuffer;
    CodeBuffer mainBuffer;
    final CodeBuffer deferredBuffer = new CodeBuffer();
    /** Shorter access to [isolatePropertiesName]. Both here in the code, as
        well as in the generated code. */
    String isolateProperties;
    String classesCollector;
    Set<ClassElement> neededClasses;
    // TODO(ngeoffray): remove this field.
    Set<ClassElement> instantiatedClasses;
  
    JavaScriptBackend get backend => compiler.backend;
  
  
negative.code:    */
    void generateClass(ClassElement classElement, CodeBuffer buffer) {
      assert(invariant(classElement, classElement.isDeclaration));
      assert(invariant(classElement, !classElement.isNative()));
  
      needsDefineClass = true;
      String className = namer.getName(classElement);
  