Expose Service Describer in Dart mojo package

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

Index: mojo/dart/packages/mojo_services/lib/mojo/web_socket.mojom.dart
diff --git a/mojo/dart/packages/mojo_services/lib/mojo/web_socket.mojom.dart b/mojo/dart/packages/mojo_services/lib/mojo/web_socket.mojom.dart
index e5791b4132f43498d2e7c9b203fb769baf152837..6c4f27ca7e097400ad66df45ed861337c8d6f7b4 100644
--- a/mojo/dart/packages/mojo_services/lib/mojo/web_socket.mojom.dart
+++ b/mojo/dart/packages/mojo_services/lib/mojo/web_socket.mojom.dart
@@ -946,11 +946,14 @@ class WebSocketMessageType extends bindings.MojoEnum {
 
 
 class _WebSocketServiceDescription 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 WebSocket {
@@ -1174,8 +1177,13 @@ class WebSocketStub extends bindings.Stub {
 
   int get version => 0;
 
-  service_describer.ServiceDescription get serviceDescription =>
-    new _WebSocketServiceDescription();
+  static service_describer.ServiceDescription _cachedServiceDescription;
+  static service_describer.ServiceDescription get serviceDescription {
+    if (_cachedServiceDescription == null) {
+      _cachedServiceDescription = new _WebSocketServiceDescription();
+    }
+    return _cachedServiceDescription;
+  }
 }
 
 const int _WebSocketClient_didConnectName = 0;
@@ -1187,11 +1195,14 @@ const int _WebSocketClient_didCloseName = 4;
 
 
 class _WebSocketClientServiceDescription 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 WebSocketClient {
@@ -1428,8 +1439,13 @@ class WebSocketClientStub extends bindings.Stub {
 
   int get version => 0;
 
-  service_describer.ServiceDescription get serviceDescription =>
-    new _WebSocketClientServiceDescription();
+  static service_describer.ServiceDescription _cachedServiceDescription;
+  static service_describer.ServiceDescription get serviceDescription {
+    if (_cachedServiceDescription == null) {
+      _cachedServiceDescription = new _WebSocketClientServiceDescription();
+    }
+    return _cachedServiceDescription;
+  }
 }