Rename the plugin location key and directory name

pkg/analysis_server/test/src/plugin/plugin_watcher_test.dart

 // Copyright (c) 2017, 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.
 
 import 'dart:async';
 import 'dart:typed_data';
 
+import 'package:analysis_server/src/plugin/plugin_locator.dart';
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
 import 'package:analysis_server/src/plugin/plugin_watcher.dart';
 import 'package:analyzer/context/context_root.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/source/package_map_resolver.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/dart/analysis/file_state.dart';
 import 'package:analyzer/src/generated/engine.dart' show AnalysisOptionsImpl;
 import 'package:analyzer/src/generated/source.dart';
 import 'package:front_end/src/base/performace_logger.dart';
@@ skipping 38 matching lines @@
     await driver.computeResult('package:pkg1/test1.dart');
     expect(manager.addedContextRoots, isEmpty);
     //
     // Use a file that imports a package with a plugin.
     //
     resourceProvider.newFile(
         resourceProvider.convertPath('/pkg2/lib/pkg2.dart'), '');
     resourceProvider.newFile(
         resourceProvider.convertPath('/pkg2/pubspec.yaml'), 'name: pkg2');
     resourceProvider.newFile(
-        resourceProvider
-            .convertPath('/pkg2/tools/analysis_plugin/bin/plugin.dart'),
+        resourceProvider.convertPath(
+            '/pkg2/${PluginLocator.toolsFolderName}/${PluginLocator.defaultPluginFolderName}/bin/plugin.dart'),
         '');
     await driver.computeResult('package:pkg2/pk2.dart');
     //
     // Wait until the timer associated with the driver's FileSystemState is
     // guaranteed to have expired and the list of changed files will have been
     // delivered.
     //
     await new Future.delayed(new Duration(seconds: 1));
     expect(manager.addedContextRoots, hasLength(1));
   }
@@ skipping 70 matching lines @@
     return null;
   }
 
   noSuchMethod(Invocation invocation) => super.noSuchMethod(invocation);
 
   @override
   void removedContextRoot(ContextRoot contextRoot) {
     removedContextRoots.add(contextRoot);
   }
 }