Mojo C++ Bindings: Extract AssociatedGroupController from MultiplexRouter

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

Index: mojo/public/cpp/bindings/lib/interface_ptr_state.h
diff --git a/mojo/public/cpp/bindings/lib/interface_ptr_state.h b/mojo/public/cpp/bindings/lib/interface_ptr_state.h
index 2aae4e61b28ce3cd53d9bde41f87be87675405d9..3d3bb149835b4ae060bf05d3051b09324648af0c 100644
--- a/mojo/public/cpp/bindings/lib/interface_ptr_state.h
+++ b/mojo/public/cpp/bindings/lib/interface_ptr_state.h
@@ -19,11 +19,11 @@
 #include "base/memory/ref_counted.h"
 #include "base/single_thread_task_runner.h"
 #include "mojo/public/cpp/bindings/associated_group.h"
+#include "mojo/public/cpp/bindings/interface_endpoint_client.h"
+#include "mojo/public/cpp/bindings/interface_id.h"
 #include "mojo/public/cpp/bindings/interface_ptr_info.h"
 #include "mojo/public/cpp/bindings/lib/control_message_proxy.h"
 #include "mojo/public/cpp/bindings/lib/filter_chain.h"
-#include "mojo/public/cpp/bindings/lib/interface_endpoint_client.h"
-#include "mojo/public/cpp/bindings/lib/interface_id.h"
 #include "mojo/public/cpp/bindings/lib/message_header_validator.h"
 #include "mojo/public/cpp/bindings/lib/multiplex_router.h"
 #include "mojo/public/cpp/bindings/lib/router.h"
@@ -330,7 +330,8 @@ class InterfacePtrState<Interface, true> {
         base::WrapUnique(new typename Interface::ResponseValidator_()), false,
         std::move(runner_)));
     proxy_.reset(new Proxy(endpoint_client_.get()));
-    proxy_->serialization_context()->router = endpoint_client_->router();
+    proxy_->serialization_context()->group_controller =
+        endpoint_client_->group_controller();
   }
 
   void OnQueryVersion(const base::Callback<void(uint32_t)>& callback,