Mojo C++ bindings: introduce an optional array to store transferred interface IDs in messages.

mojo/public/cpp/bindings/lib/multiplex_router.h

Index: mojo/public/cpp/bindings/lib/multiplex_router.h
diff --git a/mojo/public/cpp/bindings/lib/multiplex_router.h b/mojo/public/cpp/bindings/lib/multiplex_router.h
index c1e02984401bf5e6671e9793fc5e4f680da7190a..ac10f931d4d12c477db8fc5ec90f6430a7017780 100644
--- a/mojo/public/cpp/bindings/lib/multiplex_router.h
+++ b/mojo/public/cpp/bindings/lib/multiplex_router.h
@@ -154,6 +154,7 @@ class MOJO_CPP_BINDINGS_EXPORT MultiplexRouter
 
  private:
   class InterfaceEndpoint;
+  class IncomingMessageWrapper;
   struct Task;
 
   ~MultiplexRouter() override;
@@ -208,7 +209,7 @@ class MOJO_CPP_BINDINGS_EXPORT MultiplexRouter
       ClientCallBehavior client_call_behavior,
       base::SingleThreadTaskRunner* current_task_runner);
   bool ProcessIncomingMessage(
-      Message* message,
+      IncomingMessageWrapper* message_wrapper,
       ClientCallBehavior client_call_behavior,
       base::SingleThreadTaskRunner* current_task_runner);