Dart: Removes need to call listen().

mojo/dart/test/interface_test.dart

Index: mojo/dart/test/interface_test.dart
diff --git a/mojo/dart/test/interface_test.dart b/mojo/dart/test/interface_test.dart
index 18c47331bb870d58c6242acf779a10356c95a477..20c384d17654476c91c73018f2e43b8adf311b6c 100644
--- a/mojo/dart/test/interface_test.dart
+++ b/mojo/dart/test/interface_test.dart
@@ -111,9 +111,8 @@ class EchoStub extends bindings.Stub {
 
 
 class EchoProxy extends bindings.Proxy {
-  EchoProxy(core.MojoMessagePipeEndpoint endpoint, {bool doListen: true,
-      Function onClosed})
-      : super.fromEndpoint(endpoint, doListen: doListen, onClosed: onClosed);
+  EchoProxy(core.MojoMessagePipeEndpoint endpoint)
+      : super.fromEndpoint(endpoint);
 
   Future<EchoStringResponse> echoString(String a) {
     // compose message.
@@ -195,9 +194,8 @@ Future<bool> runOnClosedTest() async {
   var testCompleter = new Completer();
 
   var pipe = new core.MojoMessagePipe();
-  var proxy = new EchoProxy(pipe.endpoints[0], onClosed: () {
-    testCompleter.complete(true);
-  });
+  var proxy = new EchoProxy(pipe.endpoints[0]);
+  proxy.onError = () => testCompleter.complete(true);
   await Isolate.spawn(closingProviderIsolate, pipe.endpoints[1]);
   return testCompleter.future.timeout(
       new Duration(seconds: 1),