Add Windows support.

test/runner/browser/safari_test.dart

Index: test/runner/browser/safari_test.dart
diff --git a/test/runner/browser/safari_test.dart b/test/runner/browser/safari_test.dart
index ed8a7856fc8075023a54b4d14988e61caa5cfe8d..29c7b80ecefc3c787556c5c88d86f62e94a441aa 100644
--- a/test/runner/browser/safari_test.dart
+++ b/test/runner/browser/safari_test.dart
@@ -13,6 +13,7 @@ import 'package:shelf/shelf.dart' as shelf;
 import 'package:shelf/shelf_io.dart' as shelf_io;
 import 'package:shelf_web_socket/shelf_web_socket.dart';
 
+import '../../io.dart';
 import '../../utils.dart';
 
 void main() {
@@ -137,6 +138,6 @@ webSocket.addEventListener("open", function() {
     var safari = new Safari("http://dart-lang.org",
         executable: "_does_not_exist");
     expect(safari.onExit, throwsA(isApplicationException(startsWith(
-        "Failed to start Safari: No such file or directory"))));
+        "Failed to start Safari: $noSuchFileMessage"))));
   });
 }