More fixes for testing under windows

pkg/analyzer/lib/file_system/memory_file_system.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.file_system.memory_file_system;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:convert';
 import 'dart:core';
@@ skipping 18 matching lines @@
       new HashMap<String, List<StreamController<WatchEvent>>>();
   int nextStamp = 0;
 
   final pathos.Context _pathContext;
 
   @override
   final AbsolutePathContext absolutePathContext;
 
   MemoryResourceProvider(
       {pathos.Context context, @deprecated bool isWindows: false})
-      : _pathContext = context ?? pathos.context,
-        absolutePathContext = new AbsolutePathContext(
-            pathos.Style.platform == pathos.Style.windows);
+      : _pathContext = (context ??= pathos.context),
+        absolutePathContext =
+            new AbsolutePathContext(context.style == pathos.Style.windows);
 
   @override
   pathos.Context get pathContext => _pathContext;
 
   /**
    * Convert the given posix [path] to conform to this provider's path context.
    *
    * This is a utility method for testing; paths passed in to other methods in
    * this class are never converted automatically.
    */
@@ skipping 358 matching lines @@
 
   @override
   File renameSync(String newPath) {
     return _provider.renameFileSync(this, newPath);
   }
 
   @override
   File resolveSymbolicLinksSync() => this;
 
   @override
-  Uri toUri() =>
-      new Uri.file(path, windows: _provider.pathContext == pathos.windows);
-
-  @override
   void writeAsBytesSync(List<int> bytes) {
     _provider._setFileContent(this, bytes);
   }
 
   @override
   void writeAsStringSync(String content) {
     _provider._setFileContent(this, UTF8.encode(content));
   }
 }
 
@@ skipping 72 matching lines @@
   @override
   bool isOrContains(String path) {
     if (path == this.path) {
       return true;
     }
     return contains(path);
   }
 
   @override
   Folder resolveSymbolicLinksSync() => this;
-
-  @override
-  Uri toUri() =>
-      new Uri.directory(path, windows: _provider.pathContext == pathos.windows);
 }
 
 /**
  * An in-memory implementation of [Resource].
  */
 abstract class _MemoryResource implements Resource {
   final MemoryResourceProvider _provider;
   @override
   final String path;
 
@@ skipping 33 matching lines @@
   @override
   bool operator ==(other) {
     if (runtimeType != other.runtimeType) {
       return false;
     }
     return path == other.path;
   }
 
   @override
   String toString() => path;
+
+  @override
+  Uri toUri() => _provider.pathContext.toUri(path);
 }