Dart: Use a RawReceivePort to receive events for Mojo handles.

services/dart/test/pingpong_target/lib/main.dart

Index: services/dart/test/pingpong_target/lib/main.dart
diff --git a/services/dart/test/pingpong_target/lib/main.dart b/services/dart/test/pingpong_target/lib/main.dart
index 0d83133a4cb73294dc9e4a908967cd611bcd1f24..54d3a5325991020e5bdc03b4d1eb0cdf20e30305 100644
--- a/services/dart/test/pingpong_target/lib/main.dart
+++ b/services/dart/test/pingpong_target/lib/main.dart
@@ -28,10 +28,12 @@ class PingPongServiceImpl implements PingPongService {
 
   // These methods are unimplemented; they merely throw on invocation.
   Future<PingPongServicePingTargetUrlResponseParams> pingTargetUrl(
-          String url, int count, [Function responseFactory]) =>
+          String url, int count,
+          [Function responseFactory]) =>
       throw "Unimplemented";
   Future<PingPongServicePingTargetServiceResponseParams> pingTargetService(
-          Object service, int count, [Function responseFactory]) =>
+          Object service, int count,
+          [Function responseFactory]) =>
       throw "Unimplemented";
   void getPingPongService(Object service) => throw "Unimplemented";
 
@@ -53,7 +55,7 @@ class PingPongApplication extends Application {
     connection.provideService(PingPongServiceName,
         (endpoint) => new PingPongServiceImpl(this, endpoint));
     // Close the application when the first connection goes down.
-    connection.onError = closeApplication;
+    connection.onError = ((_) => closeApplication());
   }
 
   Future closeApplication() async {