Use OnceCallback for Mojo binding connection error handlers.

mojo/public/cpp/bindings/connector.h

 // Copyright 2013 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_CONNECTOR_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_CONNECTOR_H_
 
 #include <memory>
+#include <utility>
 
 #include "base/callback.h"
 #include "base/compiler_specific.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"
 #include "mojo/public/cpp/bindings/bindings_export.h"
 #include "mojo/public/cpp/bindings/message.h"
@@ skipping 44 matching lines @@
   // Errors from incoming receivers will force the connector into an error
   // state, where no more messages will be processed. This method is used
   // during testing to prevent that from happening.
   void set_enforce_errors_from_incoming_receiver(bool enforce) {
     DCHECK(thread_checker_.CalledOnValidThread());
     enforce_errors_from_incoming_receiver_ = enforce;
   }
 
   // Sets the error handler to receive notifications when an error is
   // encountered while reading from the pipe or waiting to read from the pipe.
-  void set_connection_error_handler(const base::Closure& error_handler) {
+  void set_connection_error_handler(base::OnceClosure error_handler) {
     DCHECK(thread_checker_.CalledOnValidThread());
-    connection_error_handler_ = error_handler;
+    connection_error_handler_ = std::move(error_handler);
   }
 
   // Returns true if an error was encountered while reading from the pipe or
   // waiting to read from the pipe.
   bool encountered_error() const {
     DCHECK(thread_checker_.CalledOnValidThread());
     return error_;
   }
 
   // Closes the pipe. The connector is put into a quiescent state.
@@ skipping 92 matching lines @@
   // |message_pipe_| with a dummy message pipe handle (whose peer is closed).
   // If |force_async_handler| is true, |connection_error_handler_| is called
   // asynchronously.
   void HandleError(bool force_pipe_reset, bool force_async_handler);
 
   // Cancels any calls made to |waiter_|.
   void CancelWait();
 
   void EnsureSyncWatcherExists();
 
-  base::Closure connection_error_handler_;
+  base::OnceClosure connection_error_handler_;
 
   ScopedMessagePipeHandle message_pipe_;
   MessageReceiver* incoming_receiver_ = nullptr;
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   std::unique_ptr<SimpleWatcher> handle_watcher_;
 
   bool error_ = false;
   bool drop_writes_ = false;
   bool enforce_errors_from_incoming_receiver_ = true;
@@ skipping 33 matching lines @@
   // transferred (i.e., when |connected_| is set to false).
   base::WeakPtr<Connector> weak_self_;
   base::WeakPtrFactory<Connector> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(Connector);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_CONNECTOR_H_