Expose Service Describer in Dart mojo package

mojo/dart/packages/mojo_services/lib/mojo/udp_socket.mojom.dart

Index: mojo/dart/packages/mojo_services/lib/mojo/udp_socket.mojom.dart
diff --git a/mojo/dart/packages/mojo_services/lib/mojo/udp_socket.mojom.dart b/mojo/dart/packages/mojo_services/lib/mojo/udp_socket.mojom.dart
index 06f6612808e9a6f54e72dcae0c4563e973375168..2ec5d7ad3f3be0016ee1d3f0b2898c22e8b0d0f8 100644
--- a/mojo/dart/packages/mojo_services/lib/mojo/udp_socket.mojom.dart
+++ b/mojo/dart/packages/mojo_services/lib/mojo/udp_socket.mojom.dart
@@ -1302,11 +1302,14 @@ const int _UdpSocket_sendToName = 7;
 
 
 class _UdpSocketServiceDescription implements service_describer.ServiceDescription {
-  dynamic getTopLevelInterface([Function responseFactory]) => null;
+  dynamic getTopLevelInterface([Function responseFactory]) =>
+      responseFactory(null);
 
-  dynamic getTypeDefinition(String typeKey, [Function responseFactory]) => null;
+  dynamic getTypeDefinition(String typeKey, [Function responseFactory]) =>
+      responseFactory(null);
 
-  dynamic getAllTypeDefinitions([Function responseFactory]) => null;
+  dynamic getAllTypeDefinitions([Function responseFactory]) =>
+      responseFactory(null);
 }
 
 abstract class UdpSocket {
@@ -1880,8 +1883,13 @@ class UdpSocketStub extends bindings.Stub {
 
   int get version => 0;
 
-  service_describer.ServiceDescription get serviceDescription =>
-    new _UdpSocketServiceDescription();
+  static service_describer.ServiceDescription _cachedServiceDescription;
+  static service_describer.ServiceDescription get serviceDescription {
+    if (_cachedServiceDescription == null) {
+      _cachedServiceDescription = new _UdpSocketServiceDescription();
+    }
+    return _cachedServiceDescription;
+  }
 }
 
 const int _UdpSocketReceiver_onReceivedName = 0;
@@ -1889,11 +1897,14 @@ const int _UdpSocketReceiver_onReceivedName = 0;
 
 
 class _UdpSocketReceiverServiceDescription implements service_describer.ServiceDescription {
-  dynamic getTopLevelInterface([Function responseFactory]) => null;
+  dynamic getTopLevelInterface([Function responseFactory]) =>
+      responseFactory(null);
 
-  dynamic getTypeDefinition(String typeKey, [Function responseFactory]) => null;
+  dynamic getTypeDefinition(String typeKey, [Function responseFactory]) =>
+      responseFactory(null);
 
-  dynamic getAllTypeDefinitions([Function responseFactory]) => null;
+  dynamic getAllTypeDefinitions([Function responseFactory]) =>
+      responseFactory(null);
 }
 
 abstract class UdpSocketReceiver {
@@ -2066,8 +2077,13 @@ class UdpSocketReceiverStub extends bindings.Stub {
 
   int get version => 0;
 
-  service_describer.ServiceDescription get serviceDescription =>
-    new _UdpSocketReceiverServiceDescription();
+  static service_describer.ServiceDescription _cachedServiceDescription;
+  static service_describer.ServiceDescription get serviceDescription {
+    if (_cachedServiceDescription == null) {
+      _cachedServiceDescription = new _UdpSocketReceiverServiceDescription();
+    }
+    return _cachedServiceDescription;
+  }
 }