Move Modifier out of the public API

pkg/analyzer/test/enum_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.
 
 library analyzer.test.enum_test;
 
 import 'dart:mirrors';
 
 import 'package:analyzer/dart/element/element.dart';
+import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
 import 'package:unittest/unittest.dart';
 
 import 'reflective_tests.dart';
 import 'utils.dart';
@@ skipping 179 matching lines @@
 
     // Check that the set of ordinals runs from 0 to N-1, where N is the number
     // of enumerated values.
     Set<int> expectedOrdinals = new Set<int>();
     for (int i = 0; i < numValues; i++) {
       expectedOrdinals.add(i);
     }
     expect(ordinals.keys.toSet(), equals(expectedOrdinals));
   }
 }