Remove AsyncError with Expando.

sdk/lib/_internal/compiler/samples/leap/leap_server.dart

Index: sdk/lib/_internal/compiler/samples/leap/leap_server.dart
diff --git a/sdk/lib/_internal/compiler/samples/leap/leap_server.dart b/sdk/lib/_internal/compiler/samples/leap/leap_server.dart
index d898f594e434a476fe29357e6554ba72a2ea2c99..1f9d63f94d82b44adb24eb41c0511911081086c7 100644
--- a/sdk/lib/_internal/compiler/samples/leap/leap_server.dart
+++ b/sdk/lib/_internal/compiler/samples/leap/leap_server.dart
@@ -82,11 +82,11 @@ class Conversation {
     new Conversation(request, request.response).handle();
   }
 
-  static onError(AsyncError e) {
-    if (e.error is HttpParserException) {
-      print('Error: ${e.error.message}');
+  static onError(error) {
+    if (error is HttpParserException) {
+      print('Error: ${error.message}');
     } else {
-      print('Error: ${e.error}');
+      print('Error: ${error}');
     }
   }
 
@@ -116,7 +116,7 @@ main() {
     print('HTTP server started on http://$host:${server.port}/');
     server.listen(Conversation.onRequest, onError: Conversation.onError);
   }).catchError((e) {
-    print("HttpServer.bind error: ${e.error}");
+    print("HttpServer.bind error: $e");
     exit(1);
   });
 }