Reapply "Add "load from .dill" file capability and run a white-box test.""

pkg/compiler/lib/src/kernel/world_builder.dart

 // Copyright (c) 2017, 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.kernel.world_builder;
 
 import 'package:kernel/ast.dart' as ir;
 
 import '../common.dart';
 import '../common/backend_api.dart';
-import '../common/names.dart';
 import '../compile_time_constants.dart';
 import '../constants/constant_system.dart';
 import '../constants/constructors.dart';
 import '../constants/evaluation.dart';
 import '../constants/expressions.dart';
 import '../constants/values.dart';
 import '../common_elements.dart';
 import '../elements/elements.dart';
 import '../elements/entities.dart';
 import '../elements/types.dart';
@@ skipping 823 matching lines @@
   }
 
   InterfaceType getMixinTypeForClass(KClass cls) {
     KClassEnv env = builder._classEnvs[cls.classIndex];
     ir.Supertype mixedInType = env.cls.mixedInType;
     if (mixedInType == null) return null;
     return builder.createInterfaceType(
         mixedInType.classNode, mixedInType.typeArguments);
   }
 }