Dart: Removes need to call listen().

mojo/public/dart/src/codec.dart

Index: mojo/public/dart/src/codec.dart
diff --git a/mojo/public/dart/src/codec.dart b/mojo/public/dart/src/codec.dart
index 81c2523be53f4c53dd836b3320ecf3ae1abe5ac4..1da160fcb22c3e186a6989d65093fbf7707250f8 100644
--- a/mojo/public/dart/src/codec.dart
+++ b/mojo/public/dart/src/codec.dart
@@ -205,6 +205,7 @@ class Encoder {
     }
     var pipe = new core.MojoMessagePipe();
     interface.bind(pipe.endpoints[0]);
+    interface.listen();
     encodeMessagePipeHandle(pipe.endpoints[1], offset, nullable);
   }
 
@@ -215,6 +216,7 @@ class Encoder {
     }
     var pipe = new core.MojoMessagePipe();
     client.impl.bind(pipe.endpoints[0]);
+    client.impl.listen();
     encodeMessagePipeHandle(pipe.endpoints[1], offset, nullable);
   }