Remove several references to JavaFile

pkg/analyzer/lib/source/embedder.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.
 
 @deprecated
 library analyzer.source.embedder;
 
 import 'dart:collection' show HashMap;
 import 'dart:core' hide Resource;
+import 'dart:io' as io;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/source/package_map_provider.dart'
     show PackageMapProvider;
 import 'package:analyzer/src/generated/java_core.dart';
 import 'package:analyzer/src/generated/java_io.dart' show JavaFile;
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/sdk_io.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/source_io.dart' show FileBasedSource;
@@ skipping 48 matching lines @@
     }
     SdkLibrary library = getSdkLibrary(libraryName);
     if (library == null) {
       return null;
     }
     String srcPath;
     if (relativePath.isEmpty) {
       srcPath = library.path;
     } else {
       String libraryPath = library.path;
-      int index = libraryPath.lastIndexOf(JavaFile.separator);
+      int index = libraryPath.lastIndexOf(io.Platform.pathSeparator);
       if (index == -1) {
         index = libraryPath.lastIndexOf('/');
         if (index == -1) {
           return null;
         }
       }
       String prefix = libraryPath.substring(0, index + 1);
       srcPath = '$prefix$relativePath';
     }
-    String filePath = srcPath.replaceAll('/', JavaFile.separator);
+    String filePath = srcPath.replaceAll('/', io.Platform.pathSeparator);
     try {
       JavaFile file = new JavaFile(filePath);
       return new FileBasedSource(file, parseUriWithException(dartUri));
     } on URISyntaxException {
       return null;
     }
   }
 
   /// Install the mapping from [name] to [libDir]/[file].
   void _processEmbeddedLibs(String name, String file, Folder libDir) {
@@ skipping 77 matching lines @@
   @override
   Uri restoreAbsolute(Source source) {
     String path = source.fullName;
     if (path.length > 3 && path[1] == ':' && path[2] == '\\') {
       path = '/${path[0]}:${path.substring(2).replaceAll('\\', '/')}';
     }
     Source sdkSource = dartSdk.fromFileUri(Uri.parse('file://$path'));
     return sdkSource?.uri;
   }
 }