Expose Service Describer in Dart mojo package

mojo/dart/packages/mojo_services/lib/mojo/gfx/composition/resources.mojom.dart

Index: mojo/dart/packages/mojo_services/lib/mojo/gfx/composition/resources.mojom.dart
diff --git a/mojo/dart/packages/mojo_services/lib/mojo/gfx/composition/resources.mojom.dart b/mojo/dart/packages/mojo_services/lib/mojo/gfx/composition/resources.mojom.dart
index 9714091b3423f55eb1d6f88af85a5a57896423d1..a8c0177c2cc21baf2a11f2b688d6826c217c13a1 100644
--- a/mojo/dart/packages/mojo_services/lib/mojo/gfx/composition/resources.mojom.dart
+++ b/mojo/dart/packages/mojo_services/lib/mojo/gfx/composition/resources.mojom.dart
@@ -375,11 +375,14 @@ const int _MailboxTextureCallback_onMailboxTextureReleasedName = 0;
 
 
 class _MailboxTextureCallbackServiceDescription 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 MailboxTextureCallback {
@@ -549,7 +552,7 @@ class MailboxTextureCallbackStub extends bindings.Stub {
 
   int get version => 0;
 
-  service_describer.ServiceDescription get serviceDescription =>
+  static service_describer.ServiceDescription get serviceDescription =>
     new _MailboxTextureCallbackServiceDescription();
 }