Use OnceCallback for Mojo binding connection error handlers.

mojo/public/cpp/bindings/interface_endpoint_client.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_INTERFACE_ENDPOINT_CLIENT_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_ENDPOINT_CLIENT_H_
 
 #include <stdint.h>
 
 #include <map>
 #include <memory>
+#include <utility>
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/optional.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_checker.h"
@@ skipping 22 matching lines @@
   InterfaceEndpointClient(ScopedInterfaceEndpointHandle handle,
                           MessageReceiverWithResponderStatus* receiver,
                           std::unique_ptr<MessageReceiver> payload_validator,
                           bool expect_sync_requests,
                           scoped_refptr<base::SingleThreadTaskRunner> runner,
                           uint32_t interface_version);
   ~InterfaceEndpointClient() override;
 
   // Sets the error handler to receive notifications when an error is
   // encountered.
-  void set_connection_error_handler(const base::Closure& error_handler) {
+  void set_connection_error_handler(base::OnceClosure error_handler) {
     DCHECK(thread_checker_.CalledOnValidThread());
-    error_handler_ = error_handler;
+    error_handler_ = std::move(error_handler);
     error_with_reason_handler_.Reset();
   }
 
   void set_connection_error_with_reason_handler(
-      const ConnectionErrorWithReasonCallback& error_handler) {
+      ConnectionErrorWithReasonCallback error_handler) {
     DCHECK(thread_checker_.CalledOnValidThread());
-    error_with_reason_handler_ = error_handler;
+    error_with_reason_handler_ = std::move(error_handler);
     error_handler_.Reset();
   }
 
   // Returns true if an error was encountered.
   bool encountered_error() const {
     DCHECK(thread_checker_.CalledOnValidThread());
     return encountered_error_;
   }
 
   // Returns true if this endpoint has any pending callbacks.
@@ skipping 91 matching lines @@
 
   MessageReceiverWithResponderStatus* const incoming_receiver_ = nullptr;
   HandleIncomingMessageThunk thunk_;
   FilterChain filters_;
 
   AsyncResponderMap async_responders_;
   SyncResponseMap sync_responses_;
 
   uint64_t next_request_id_ = 1;
 
-  base::Closure error_handler_;
+  base::OnceClosure error_handler_;
   ConnectionErrorWithReasonCallback error_with_reason_handler_;
   bool encountered_error_ = false;
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
   internal::ControlMessageProxy control_message_proxy_;
   internal::ControlMessageHandler control_message_handler_;
 
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<InterfaceEndpointClient> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(InterfaceEndpointClient);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_ENDPOINT_CLIENT_H_