Make elements/names.dart its own library

pkg/compiler/lib/src/elements/names.dart

 // Copyright (c) 2014, 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 elements;
+library dart2js.elements.names;
+
+import 'package:front_end/src/fasta/scanner/characters.dart' show $_;
+import 'entities.dart' show LibraryEntity;
 
 /// A [Name] represents the abstraction of a Dart identifier which takes privacy
 /// and setter into account.
 // TODO(johnniwinther): Try to share logic with [Selector].
 abstract class Name {
   /// Create a [Name] for an identifier [text]. If [text] begins with '_' a
   /// private name with respect to [library] is created. If [isSetter] is `true`
   /// the created name represents the setter name 'text='.
   factory Name(String text, LibraryEntity library, {bool isSetter: false}) {
     if (isPrivateName(text)) {
@@ skipping 75 matching lines @@
 
   PrivateName(String text, this.library, {bool isSetter: false})
       : super(text, isSetter: isSetter);
 
   Name get getter => isSetter ? new PrivateName(text, library) : this;
 
   Name get setter {
     return isSetter ? this : new PrivateName(text, library, isSetter: true);
   }
 
-  bool isAccessibleFrom(LibraryElement element) => library == element;
+  bool isAccessibleFrom(LibraryEntity element) => library == element;
 
   bool get isPrivate => true;
 
   int get hashCode => super.hashCode + 13 * library.hashCode;
 
   bool operator ==(other) {
     if (other is! PrivateName) return false;
     return super == (other) && library == other.library;
   }
 
   String toString() => '${library.name}#${super.toString()}';
 }