Create response_parameters as part of mojom

mojo/public/bindings/tests/sample_service.mojom

Index: mojo/public/bindings/tests/sample_service.mojom
diff --git a/mojo/public/bindings/tests/sample_service.mojom b/mojo/public/bindings/tests/sample_service.mojom
index 979ec39c5731294e58d711b7f9889b70dcb66660..d64c7d396ba27f0b2abfbb9967ba24f0d225fd7c 100644
--- a/mojo/public/bindings/tests/sample_service.mojom
+++ b/mojo/public/bindings/tests/sample_service.mojom
@@ -52,7 +52,7 @@ struct DefaultsTest {
 };
 
 interface Port {
-  PostMessage(string message_text @0) @0;
+  PostMessage@0(string message_text @0);
 };
 
 [Peer=ServiceClient]
@@ -61,12 +61,12 @@ interface Service {
     BAZ_REGULAR = 0,
     BAZ_EXTRA
   };
-  Frobinate(Foo foo @0, int32 baz @1, Port port @2) @0;
+  Frobinate@0(Foo foo @0, int32 baz @1, Port port @2);
 };
 
 [Peer=Service]
 interface ServiceClient {
-  DidFrobinate(int32 result @0) @0;
+  DidFrobinate@0(int32 result @0);
 };
 
 }