Pass Callback to TaskRunner by value and consume it on invocation (1)

base/task_runner.cc

 // Copyright (c) 2012 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.
 
 #include "base/task_runner.h"
 
 #include <utility>
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/threading/post_task_and_reply_impl.h"
 
 namespace base {
 
 namespace {
 
 // TODO(akalin): There's only one other implementation of
 // PostTaskAndReplyImpl in WorkerPool.  Investigate whether it'll be
 // possible to merge the two.
 class PostTaskAndReplyTaskRunner : public internal::PostTaskAndReplyImpl {
  public:
   explicit PostTaskAndReplyTaskRunner(TaskRunner* destination);
 
  private:
   bool PostTask(const tracked_objects::Location& from_here,
-                const Closure& task) override;
+                Closure task) override;
 
   // Non-owning.
   TaskRunner* destination_;
 };
 
 PostTaskAndReplyTaskRunner::PostTaskAndReplyTaskRunner(
     TaskRunner* destination) : destination_(destination) {
   DCHECK(destination_);
 }
 
 bool PostTaskAndReplyTaskRunner::PostTask(
     const tracked_objects::Location& from_here,
-    const Closure& task) {
-  return destination_->PostTask(from_here, task);
+    Closure task) {
+  return destination_->PostTask(from_here, std::move(task));
 }
 
 }  // namespace
 
 bool TaskRunner::PostTask(const tracked_objects::Location& from_here,
-                          const Closure& task) {
-  return PostDelayedTask(from_here, task, base::TimeDelta());
+                          Closure task) {
+  return PostDelayedTask(from_here, std::move(task), base::TimeDelta());
 }
 
 bool TaskRunner::PostTaskAndReply(const tracked_objects::Location& from_here,
                                   Closure task,
                                   Closure reply) {
   return PostTaskAndReplyTaskRunner(this).PostTaskAndReply(
       from_here, std::move(task), std::move(reply));
 }
 
 TaskRunner::TaskRunner() {}
 
 TaskRunner::~TaskRunner() {}
 
 void TaskRunner::OnDestruct() const {
   delete this;
 }
 
 void TaskRunnerTraits::Destruct(const TaskRunner* task_runner) {
   task_runner->OnDestruct();
 }
 
 }  // namespace base