Avoid use of empty string as a property name.

sdk/lib/_internal/compiler/implementation/js_emitter/class_emitter.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;
 
 class ClassEmitter extends CodeEmitterHelper {
   /**
    * Documentation wanted -- johnniwinther
    *
@@ skipping 18 matching lines @@
     }
     String runtimeName =
         namer.getPrimitiveInterceptorRuntimeName(classElement);
 
     if (classElement.isMixinApplication) {
       String mixinName = namer.getNameOfClass(computeMixinClass(classElement));
       superName = '$superName+$mixinName';
       task.needsMixinSupport = true;
     }
 
-    ClassBuilder builder = new ClassBuilder();
+    ClassBuilder builder = new ClassBuilder(namer);
     emitClassConstructor(classElement, builder, runtimeName,
                          onlyForRti: onlyForRti);
     emitFields(classElement, builder, superName, onlyForRti: onlyForRti);
     emitClassGettersSetters(classElement, builder, onlyForRti: onlyForRti);
     emitInstanceMembers(classElement, builder, onlyForRti: onlyForRti);
     task.typeTestEmitter.emitIsTests(classElement, builder);
     if (additionalProperties != null) {
       additionalProperties.forEach(builder.addProperty);
     }
 
@@ skipping 257 matching lines @@
       ClassElement superclass = classElement.superclass;
       bool hasSuper = superclass != null;
       if ((!typeVariableProperties.isEmpty && !hasSuper) ||
           (hasSuper && superclass.typeVariables != typeVars)) {
         classBuilder.addProperty('<>',
             new jsAst.ArrayInitializer.from(typeVariableProperties));
       }
     }
 
     List<jsAst.Property> statics = new List<jsAst.Property>();
-    ClassBuilder staticsBuilder = new ClassBuilder();
+    ClassBuilder staticsBuilder = new ClassBuilder(namer);
     if (emitFields(classElement, staticsBuilder, null, emitStatics: true)) {
       statics.add(staticsBuilder.toObjectInitializer().properties.single);
     }
 
     Map<OutputUnit, ClassBuilder> classPropertyLists =
         task.elementDescriptors.remove(classElement);
     if (classPropertyLists != null) {
       for (ClassBuilder classProperties in classPropertyLists.values) {
         // TODO(sigurdm): What about deferred?
         if (classProperties != null) {
@@ skipping 266 matching lines @@
       computeTypeVariable =
           js(r'this.$builtinTypeInfo && this.$builtinTypeInfo[#]', index);
     }
     jsAst.Expression convertRtiToRuntimeType =
         namer.elementAccess(compiler.findHelper('convertRtiToRuntimeType'));
     builder.addProperty(
         name, js.fun(
             [], [js.return_(convertRtiToRuntimeType(computeTypeVariable))]));
   }
 }