Expose Service Describer in Dart mojo package

mojo/dart/packages/mojo_services/lib/mojo/media/media_transport.mojom.dart

Index: mojo/dart/packages/mojo_services/lib/mojo/media/media_transport.mojom.dart
diff --git a/mojo/dart/packages/mojo_services/lib/mojo/media/media_transport.mojom.dart b/mojo/dart/packages/mojo_services/lib/mojo/media/media_transport.mojom.dart
index 01ed709a61234ac331776efde34348b0d14b34d7..9e321c201ba51c53367498eb7517785eac97119a 100644
--- a/mojo/dart/packages/mojo_services/lib/mojo/media/media_transport.mojom.dart
+++ b/mojo/dart/packages/mojo_services/lib/mojo/media/media_transport.mojom.dart
@@ -854,11 +854,14 @@ const int _MediaProducer_disconnectName = 1;
 
 
 class _MediaProducerServiceDescription 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 MediaProducer {
@@ -1084,8 +1087,13 @@ class MediaProducerStub extends bindings.Stub {
 
   int get version => 0;
 
-  service_describer.ServiceDescription get serviceDescription =>
-    new _MediaProducerServiceDescription();
+  static service_describer.ServiceDescription _cachedServiceDescription;
+  static service_describer.ServiceDescription get serviceDescription {
+    if (_cachedServiceDescription == null) {
+      _cachedServiceDescription = new _MediaProducerServiceDescription();
+    }
+    return _cachedServiceDescription;
+  }
 }
 
 const int _MediaPullModeProducer_getBufferName = 0;
@@ -1095,11 +1103,14 @@ const int _MediaPullModeProducer_releasePacketName = 2;
 
 
 class _MediaPullModeProducerServiceDescription 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 MediaPullModeProducer {
@@ -1383,8 +1394,13 @@ class MediaPullModeProducerStub extends bindings.Stub {
 
   int get version => 0;
 
-  service_describer.ServiceDescription get serviceDescription =>
-    new _MediaPullModeProducerServiceDescription();
+  static service_describer.ServiceDescription _cachedServiceDescription;
+  static service_describer.ServiceDescription get serviceDescription {
+    if (_cachedServiceDescription == null) {
+      _cachedServiceDescription = new _MediaPullModeProducerServiceDescription();
+    }
+    return _cachedServiceDescription;
+  }
 }
 
 const int _MediaConsumer_setBufferName = 0;
@@ -1393,11 +1409,14 @@ const int _MediaConsumer_pushPacketName = 1;
 
 
 class _MediaConsumerServiceDescription 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 MediaConsumer {
@@ -1666,8 +1685,13 @@ class MediaConsumerStub extends bindings.Stub {
 
   int get version => 0;
 
-  service_describer.ServiceDescription get serviceDescription =>
-    new _MediaConsumerServiceDescription();
+  static service_describer.ServiceDescription _cachedServiceDescription;
+  static service_describer.ServiceDescription get serviceDescription {
+    if (_cachedServiceDescription == null) {
+      _cachedServiceDescription = new _MediaConsumerServiceDescription();
+    }
+    return _cachedServiceDescription;
+  }
 }