Use OnceCallback for Mojo binding connection error handlers.

mojo/public/cpp/bindings/binding.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_BINDING_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_BINDING_H_
 
 #include <string>
 #include <utility>
 
@@ skipping 166 matching lines @@
     CHECK(!HasAssociatedInterfaces());
     return internal_state_.Unbind();
   }
 
   // Sets an error handler that will be called if a connection error occurs on
   // the bound message pipe.
   //
   // This method may only be called after this Binding has been bound to a
   // message pipe. The error handler will be reset when this Binding is unbound
   // or closed.
-  void set_connection_error_handler(const base::Closure& error_handler) {
+  void set_connection_error_handler(base::OnceClosure error_handler) {
     DCHECK(is_bound());
-    internal_state_.set_connection_error_handler(error_handler);
+    internal_state_.set_connection_error_handler(std::move(error_handler));
   }
 
   void set_connection_error_with_reason_handler(
-      const ConnectionErrorWithReasonCallback& error_handler) {
+      ConnectionErrorWithReasonCallback error_handler) {
     DCHECK(is_bound());
-    internal_state_.set_connection_error_with_reason_handler(error_handler);
+    internal_state_.set_connection_error_with_reason_handler(
+        std::move(error_handler));
   }
 
   // Returns the interface implementation that was previously specified. Caller
   // does not take ownership.
   Interface* impl() { return internal_state_.impl(); }
 
   // Indicates whether the binding has been completed (i.e., whether a message
   // pipe has been bound to the implementation).
   bool is_bound() const { return internal_state_.is_bound(); }
 
@@ skipping 14 matching lines @@
 
  private:
   internal::BindingState<Interface, ImplRefTraits> internal_state_;
 
   DISALLOW_COPY_AND_ASSIGN(Binding);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_BINDING_H_