Fix more tests under windows

pkg/analyzer/test/src/context/abstract_context.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.src.context.abstract_context;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/visitor.dart';
 import 'package:analyzer/file_system/file_system.dart';
@@ skipping 108 matching lines @@
     }
   }
 
   AnalysisContextImpl createAnalysisContext() {
     return new AnalysisContextImpl();
   }
 
   DartSdk createDartSdk() => new MockSdk(resourceProvider: resourceProvider);
 
   Source newSource(String path, [String content = '']) {
-    File file = resourceProvider.newFile(path, content);
+    File file =
+        resourceProvider.newFile(resourceProvider.convertPath(path), content);
     return file.createSource();
   }
 
   List<Source> newSources(Map<String, String> sourceMap) {
     List<Source> sources = <Source>[];
     sourceMap.forEach((String path, String content) {
       Source source = newSource(path, content);
       sources.add(source);
     });
     return sources;
@@ skipping 40 matching lines @@
 class _ElementVisitorFunctionWrapper extends GeneralizingElementVisitor {
   final _ElementVisitorFunction function;
 
   _ElementVisitorFunctionWrapper(this.function);
 
   visitElement(Element element) {
     function(element);
     super.visitElement(element);
   }
 }