Mojo C++ bindings: reduce references to AssociatedGroupController.

mojo/public/cpp/bindings/lib/associated_interface_ptr_state.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_LIB_ASSOCIATED_INTERFACE_PTR_STATE_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_ASSOCIATED_INTERFACE_PTR_STATE_H_
 
 #include <stdint.h>
 
 #include <algorithm>  // For |std::swap()|.
@@ skipping 84 matching lines @@
     DCHECK(info.is_valid());
 
     version_ = info.version();
     // The version is only queried from the client so the value passed here
     // will not be used.
     endpoint_client_.reset(new InterfaceEndpointClient(
         info.PassHandle(), nullptr,
         base::WrapUnique(new typename Interface::ResponseValidator_()), false,
         std::move(runner), 0u));
     proxy_.reset(new Proxy(endpoint_client_.get()));
-    proxy_->serialization_context()->group_controller =
-        endpoint_client_->group_controller();
+    if (Interface::PassesAssociatedKinds_) {
+      proxy_->serialization_context()->group_controller =
+          endpoint_client_->group_controller();
+    }
   }
 
   // After this method is called, the object is in an invalid state and
   // shouldn't be reused.
   AssociatedInterfacePtrInfo<Interface> PassInterface() {
     ScopedInterfaceEndpointHandle handle = endpoint_client_->PassHandle();
     endpoint_client_.reset();
     proxy_.reset();
     return AssociatedInterfacePtrInfo<Interface>(std::move(handle), version_);
   }
@@ skipping 38 matching lines @@
 
   uint32_t version_;
 
   DISALLOW_COPY_AND_ASSIGN(AssociatedInterfacePtrState);
 };
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_ASSOCIATED_INTERFACE_PTR_STATE_H_