Expose Service Describer in Dart mojo package

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

Index: mojo/dart/packages/mojo_services/lib/mojo/terminal/terminal.mojom.dart
diff --git a/mojo/dart/packages/mojo_services/lib/mojo/terminal/terminal.mojom.dart b/mojo/dart/packages/mojo_services/lib/mojo/terminal/terminal.mojom.dart
index ad668c290eb17479a001a8ccf9f5bb85159c6637..2424e6c6404e6f82b04bbc161466536b308539d7 100644
--- a/mojo/dart/packages/mojo_services/lib/mojo/terminal/terminal.mojom.dart
+++ b/mojo/dart/packages/mojo_services/lib/mojo/terminal/terminal.mojom.dart
@@ -726,11 +726,14 @@ const int _Terminal_setSizeName = 3;
 
 
 class _TerminalServiceDescription 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 Terminal {
@@ -1121,7 +1124,7 @@ class TerminalStub extends bindings.Stub {
 
   int get version => 0;
 
-  service_describer.ServiceDescription get serviceDescription =>
+  static service_describer.ServiceDescription get serviceDescription =>
     new _TerminalServiceDescription();
 }