Make elements/names.dart its own library

pkg/compiler/lib/src/resolution/constructors.dart

 // Copyright (c) 2015, 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.resolution.constructors;
 
 import '../common.dart';
 import '../common/resolution.dart' show Resolution;
 import '../constants/constructors.dart'
     show
         GenerativeConstantConstructor,
         RedirectingGenerativeConstantConstructor;
 import '../constants/expressions.dart';
 import '../elements/resolution_types.dart';
 import '../elements/elements.dart';
 import '../elements/modelx.dart'
     show
         ConstructorElementX,
         ErroneousConstructorElementX,
         ErroneousElementX,
         ErroneousFieldElementX,
         FieldElementX,
         InitializingFormalElementX,
         ParameterElementX;
+import '../elements/names.dart';
 import '../tree/tree.dart';
 import '../universe/call_structure.dart' show CallStructure;
 import '../universe/feature.dart' show Feature;
 import '../universe/use.dart' show StaticUse;
 import '../util/util.dart' show Link;
 import 'members.dart' show lookupInScope, ResolverVisitor;
 import 'registry.dart' show ResolutionRegistry;
 import 'resolution_common.dart' show CommonResolverVisitor;
 import 'resolution_result.dart';
 import 'scope.dart' show Scope, ExtensionScope;
@@ skipping 850 matching lines @@
     // constructors.
     return null;
   }
   // TODO(johnniwinther): Use [Name] for lookup.
   ConstructorElement constructor = cls.lookupConstructor(constructorName);
   if (constructor != null) {
     constructor = constructor.declaration;
   }
   return constructor;
 }