Mojo C++ bindings: reduce references to AssociatedGroupController.

mojo/public/cpp/bindings/associated_binding.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_ASSOCIATED_BINDING_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_ASSOCIATED_BINDING_H_
 
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 92 matching lines @@
     if (!handle.is_valid() || !handle.is_local()) {
       endpoint_client_.reset();
       return;
     }
 
     endpoint_client_.reset(new InterfaceEndpointClient(
         std::move(handle), &stub_,
         base::WrapUnique(new typename Interface::RequestValidator_()),
         Interface::HasSyncMethods_, std::move(runner), Interface::Version_));
 
-    stub_.serialization_context()->group_controller =
-        endpoint_client_->group_controller();
+    if (Interface::PassesAssociatedKinds_) {
+      stub_.serialization_context()->group_controller =
+          endpoint_client_->group_controller();
+    }
   }
 
   // Adds a message filter to be notified of each incoming message before
   // dispatch. If a filter returns |false| from Accept(), the message is not
   // dispatched and the pipe is closed. Filters cannot be removed.
   void AddFilter(std::unique_ptr<MessageReceiver> filter) {
     DCHECK(endpoint_client_);
     endpoint_client_->AddFilter(std::move(filter));
   }
 
@@ skipping 65 matching lines @@
  private:
   std::unique_ptr<InterfaceEndpointClient> endpoint_client_;
   typename Interface::template Stub_<ImplRefTraits> stub_;
 
   DISALLOW_COPY_AND_ASSIGN(AssociatedBinding);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_ASSOCIATED_BINDING_H_