Make elements/names.dart its own library

pkg/compiler/lib/src/js_backend/backend.dart

 // Copyright (c) 2012, 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 js_backend.backend;
 
 import '../common.dart';
 import '../common/backend_api.dart'
     show ForeignResolver, NativeRegistry, ImpactTransformer;
 import '../common/codegen.dart' show CodegenImpact, CodegenWorkItem;
 import '../common/names.dart' show Uris;
 import '../common/resolution.dart' show Resolution, Target;
 import '../common/tasks.dart' show CompilerTask;
 import '../compiler.dart' show Compiler;
 import '../constants/constant_system.dart';
 import '../constants/expressions.dart';
 import '../constants/values.dart';
 import '../common_elements.dart' show CommonElements, ElementEnvironment;
 import '../deferred_load.dart' show DeferredLoadTask;
 import '../dump_info.dart' show DumpInfoTask;
 import '../elements/elements.dart';
 import '../elements/entities.dart';
+import '../elements/names.dart';
 import '../elements/resolution_types.dart';
 import '../elements/types.dart';
 import '../enqueue.dart'
     show
         DirectEnqueuerStrategy,
         Enqueuer,
         EnqueueTask,
         ResolutionEnqueuer,
         TreeShakingEnqueuerStrategy;
 import '../frontend_strategy.dart';
@@ skipping 1440 matching lines @@
 
   bool canUseAliasedSuperMember(MemberEntity member, Selector selector) {
     return !selector.isGetter;
   }
 
   /// Returns `true` if [member] is called from a subclass via `super`.
   bool isAliasedSuperMember(MemberEntity member) {
     return _aliasedSuperMembers.contains(member);
   }
 }