Use OnceCallback for Mojo binding connection error handlers.

mojo/public/cpp/bindings/associated_binding.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_ASSOCIATED_BINDING_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_ASSOCIATED_BINDING_H_
 
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 35 matching lines @@
   void Close();
 
   // Similar to the method above, but also specifies a disconnect reason.
   void CloseWithReason(uint32_t custom_reason, const std::string& description);
 
   // Sets an error handler that will be called if a connection error occurs.
   //
   // This method may only be called after this AssociatedBinding has been bound
   // to a message pipe. The error handler will be reset when this
   // AssociatedBinding is unbound or closed.
-  void set_connection_error_handler(const base::Closure& error_handler);
+  void set_connection_error_handler(base::OnceClosure error_handler);
 
   void set_connection_error_with_reason_handler(
-      const ConnectionErrorWithReasonCallback& error_handler);
+      ConnectionErrorWithReasonCallback error_handler);
 
   // Indicates whether the associated binding has been completed.
   bool is_bound() const { return !!endpoint_client_; }
 
   // Sends a message on the underlying message pipe and runs the current
   // message loop until its response is received. This can be used in tests to
   // verify that no message was sent on a message pipe in response to some
   // stimulus.
   void FlushForTesting();
 
@@ skipping 69 matching lines @@
 
  private:
   typename Interface::template Stub_<ImplRefTraits> stub_;
 
   DISALLOW_COPY_AND_ASSIGN(AssociatedBinding);
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_ASSOCIATED_BINDING_H_