MemoryResourceProvider always uses the current platform

pkg/analyzer/test/source/analysis_options_provider_test.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 analyzer.test.source.analysis_options_provider_test;
 
 import 'dart:core';
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
@@ skipping 102 matching lines @@
 
 abstract class AnalysisOptionsProviderTest {
   TestPathTranslator pathTranslator;
   ResourceProvider resourceProvider;
 
   AnalysisOptionsProvider provider = new AnalysisOptionsProvider();
 
   String get optionsFileName;
 
   void setUp() {
-    var rawProvider = new MemoryResourceProvider(isWindows: isWindows);
+    var rawProvider = new MemoryResourceProvider();
     resourceProvider = new TestResourceProvider(rawProvider);
     pathTranslator = new TestPathTranslator(rawProvider);
   }
 
   void test_getOptions_crawlUp_hasInFolder() {
     pathTranslator.newFolder('/foo/bar');
     pathTranslator.newFile(
         '/foo/$optionsFileName',
         r'''
 analyzer:
@@ skipping 82 matching lines @@
         expect(ignore[1], 'sdk_ext/**');
       }
     }
   }
 
   Map<String, YamlNode> _getOptions(String posixPath, {bool crawlUp: false}) {
     Resource resource = pathTranslator.getResource(posixPath);
     return provider.getOptions(resource, crawlUp: crawlUp);
   }
 }