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 ce037276316fd2c0acd74d32ebf39b4aeea9e4c8..29da473c51db2200d20b6786b6ddf8f2bf824a70 100644
--- a/mojo/public/dart/src/codec.dart
+++ b/mojo/public/dart/src/codec.dart
@@ -210,6 +210,7 @@ class Encoder {
       assert(!interface.isBound);
       var pipe = new core.MojoMessagePipe();
       interface.bind(pipe.endpoints[0]);
+      interface.listen();
       encodeMessagePipeHandle(pipe.endpoints[1], offset, nullable);
     } else if (interface is Proxy) {
       assert(interface.isBound);
@@ -232,6 +233,7 @@ class Encoder {
     }
     var pipe = new core.MojoMessagePipe();
     client.impl.bind(pipe.endpoints[0]);
+    client.impl.listen();
     encodeMessagePipeHandle(pipe.endpoints[1], offset, nullable);
   }