Stop using LibraryElement.visibleLibraries getter.

test/codegen/recorder_test.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.
 
 @TestOn('vm')
 library smoke.test.codegen.recorder_test;
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:smoke/codegen/generator.dart';
 import 'package:smoke/codegen/recorder.dart';
@@ skipping 71 matching lines @@
       recorder.lookupParent(lib.getType('A'));
       recorder.lookupParent(lib.getType('B'));
       recorder.lookupParent(lib.getType('C'));
       recorder.lookupParent(lib.getType('D'));
       recorder.lookupParent(lib.getType('E'));
       recorder.lookupParent(lib.getType('E2'));
       recorder.lookupParent(lib.getType('F'));
       recorder.lookupParent(lib.getType('F2'));
       recorder.lookupParent(lib.getType('G'));
       recorder.lookupParent(lib.getType('H'));
-      var coreLib =
-          lib.visibleLibraries.firstWhere((l) => l.displayName == 'dart.core');
+      var coreLib = lib.context.typeProvider.objectType.element.library;
       recorder.lookupParent(coreLib.getType('int'));
       recorder.lookupParent(coreLib.getType('num'));
 
       checkResults(generator,
           imports: ["import '/common.dart' as smoke_0;",],
           topLevel: 'abstract class _M0 {} // C & A\n',
           initCall: 'useGeneratedCode(new StaticConfiguration(\n'
               '    checkedMode: false,\n'
               '    parents: {\n'
               '      smoke_0.AnnotB: smoke_0.Annot,\n'
@@ skipping 668 matching lines @@
 
       class K {
         @AnnotC(named: true) int k;
         @AnnotC() int k2;
       }
       '''
 };
 
 String resolveImportUrl(LibraryElement lib) =>
     lib.isDartCore ? 'dart:core' : '/${lib.displayName}.dart';