Access BackendUsage through ClosedWorld

pkg/compiler/lib/src/js_emitter/full_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.
 
 library dart2js.js_emitter.full_emitter.class_emitter;
 
 import '../../common.dart';
 import '../../common/names.dart' show Names;
 import '../../elements/resolution_types.dart' show ResolutionDartType;
 import '../../deferred_load.dart' show OutputUnit;
@@ skipping 254 matching lines @@
     // TODO(herhut): This is a no-op. Should it be removed?
     for (Field field in cls.fields) {
       emitter.containerBuilder.addMemberField(field, builder);
     }
 
     for (Method method in cls.methods) {
       assert(invariant(classElement, method.element.isInstanceMember));
       emitter.containerBuilder.addMemberMethod(method, builder);
     }
 
-    if (classElement.isObject && backend.backendUsage.isNoSuchMethodUsed) {
+    if (classElement.isObject && closedWorld.backendUsage.isNoSuchMethodUsed) {
       // Emit the noSuchMethod handlers on the Object prototype now,
       // so that the code in the dynamicFunction helper can find
       // them. Note that this helper is invoked before analyzing the
       // full JS script.
       emitter.nsmEmitter.emitNoSuchMethodHandlers(builder.addProperty);
     }
   }
 
   /// Emits the members from the model.
   void emitRuntimeTypeInformation(Class cls, ClassBuilder builder) {
@@ skipping 156 matching lines @@
     String reflectionName = emitter.getReflectionName(selector, name);
     if (reflectionName != null) {
       var reflectable = js(
           backend.mirrorsData.isMemberAccessibleByReflection(member)
               ? '1'
               : '0');
       builder.addPropertyByName('+$reflectionName', reflectable);
     }
   }
 }