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

mojo/public/dart/mojo/lib/src/handle.dart

Index: mojo/public/dart/mojo/lib/src/handle.dart
diff --git a/mojo/public/dart/mojo/lib/src/handle.dart b/mojo/public/dart/mojo/lib/src/handle.dart
index 583877f9c24073dcd876e088692fb32ddfc5d093..d94da54676c4e53bb8d68b39966f38fe011ae55e 100644
--- a/mojo/public/dart/mojo/lib/src/handle.dart
+++ b/mojo/public/dart/mojo/lib/src/handle.dart
@@ -81,9 +81,9 @@ class MojoHandle {
     return new MojoWaitManyResult(new MojoResult(result[0]), result[1], states);
   }
 
-  static MojoResult registerFinalizer(MojoEventStream eventStream) {
+  static MojoResult registerFinalizer(MojoEventHandler eventHandler) {
     return new MojoResult(MojoHandleNatives.registerFinalizer(
-        eventStream, eventStream._handle.h));
+        eventHandler, eventHandler._handle.h));
   }
 
   static bool reportLeakedHandles() => MojoHandleNatives.reportOpenHandles();