Use OnceCallback for Mojo binding connection error handlers.

mojo/public/cpp/bindings/lib/binding_state.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_LIB_BINDING_STATE_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDING_STATE_H_
 
 #include <memory>
 #include <string>
 #include <utility>
@@ skipping 32 matching lines @@
 
   void PauseIncomingMethodCallProcessing();
   void ResumeIncomingMethodCallProcessing();
 
   bool WaitForIncomingMethodCall(
       MojoDeadline deadline = MOJO_DEADLINE_INDEFINITE);
 
   void Close();
   void CloseWithReason(uint32_t custom_reason, const std::string& description);
 
-  void set_connection_error_handler(const base::Closure& error_handler) {
+  void set_connection_error_handler(base::OnceClosure error_handler) {
     DCHECK(is_bound());
-    endpoint_client_->set_connection_error_handler(error_handler);
+    endpoint_client_->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());
-    endpoint_client_->set_connection_error_with_reason_handler(error_handler);
+    endpoint_client_->set_connection_error_with_reason_handler(
+        std::move(error_handler));
   }
 
   bool is_bound() const { return !!router_; }
 
   MessagePipeHandle handle() const {
     DCHECK(is_bound());
     return router_->handle();
   }
 
   void FlushForTesting();
@@ skipping 46 matching lines @@
  private:
   typename Interface::template Stub_<ImplRefTraits> stub_;
 
   DISALLOW_COPY_AND_ASSIGN(BindingState);
 };
 
 }  // namesapce internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_BINDING_STATE_H_