Use OnceCallback for Mojo binding connection error handlers.

mojo/public/cpp/bindings/interface_ptr.h

 // Copyright 2014 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_PTR_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_PTR_H_
 
 #include <stdint.h>
 
 #include <string>
@@ skipping 135 matching lines @@
   // Indicates whether the message pipe has encountered an error. If true,
   // method calls made on this interface will be dropped (and may already have
   // been dropped).
   bool encountered_error() const { return internal_state_.encountered_error(); }
 
   // Registers a handler to receive error notifications. The handler will be
   // called from the thread that owns this InterfacePtr.
   //
   // This method may only be called after the InterfacePtr has been bound to a
   // message pipe.
-  void set_connection_error_handler(const base::Closure& error_handler) {
-    internal_state_.set_connection_error_handler(error_handler);
+  void set_connection_error_handler(base::OnceClosure error_handler) {
+    internal_state_.set_connection_error_handler(std::move(error_handler));
   }
 
   void set_connection_error_with_reason_handler(
-      const ConnectionErrorWithReasonCallback& error_handler) {
-    internal_state_.set_connection_error_with_reason_handler(error_handler);
+      ConnectionErrorWithReasonCallback error_handler) {
+    internal_state_.set_connection_error_with_reason_handler(
+        std::move(error_handler));
   }
 
   // Unbinds the InterfacePtr and returns the information which could be used
   // to setup an InterfacePtr again. This method may be used to move the proxy
   // to a different thread (see class comments for details).
   //
   // It is an error to call PassInterface() while:
   //   - there are pending responses; or
   //     TODO: fix this restriction, it's not always obvious when there is a
   //     pending response.
@@ skipping 60 matching lines @@
         base::ThreadTaskRunnerHandle::Get()) {
   InterfacePtr<Interface> ptr;
   if (info.is_valid())
     ptr.Bind(std::move(info), std::move(runner));
   return std::move(ptr);
 }
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_INTERFACE_PTR_H_