Pass Callback by value on PostTaskAndReply family

base/task/cancelable_task_tracker.cc

 // 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.
 
 #include "base/task/cancelable_task_tracker.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 56 matching lines @@
     const tracked_objects::Location& from_here,
     const Closure& task) {
   DCHECK(sequence_checker_.CalledOnValidSequence());
 
   return PostTaskAndReply(task_runner, from_here, task, Bind(&base::DoNothing));
 }
 
 CancelableTaskTracker::TaskId CancelableTaskTracker::PostTaskAndReply(
     TaskRunner* task_runner,
     const tracked_objects::Location& from_here,
-    const Closure& task,
-    const Closure& reply) {
+    Closure task,
+    Closure reply) {
   DCHECK(sequence_checker_.CalledOnValidSequence());
 
   // We need a SequencedTaskRunnerHandle to run |reply|.
   DCHECK(base::SequencedTaskRunnerHandle::IsSet());
 
   // Owned by reply callback below.
   CancellationFlag* flag = new CancellationFlag();
 
   TaskId id = next_id_;
   next_id_++;  // int64_t is big enough that we ignore the potential overflow.
 
-  const Closure& untrack_closure =
+  Closure untrack_closure =
       Bind(&CancelableTaskTracker::Untrack, weak_factory_.GetWeakPtr(), id);
-  bool success =
-      task_runner->PostTaskAndReply(from_here,
-                                    Bind(&RunIfNotCanceled, flag, task),
-                                    Bind(&RunIfNotCanceledThenUntrack,
-                                         base::Owned(flag),
-                                         reply,
-                                         untrack_closure));
+  bool success = task_runner->PostTaskAndReply(
+      from_here, Bind(&RunIfNotCanceled, flag, std::move(task)),
+      Bind(&RunIfNotCanceledThenUntrack, base::Owned(flag), std::move(reply),
+           std::move(untrack_closure)));
 
   if (!success)
     return kBadTaskId;
 
   Track(id, flag);
   return id;
 }
 
 CancelableTaskTracker::TaskId CancelableTaskTracker::NewTrackedTaskId(
     IsCanceledCallback* is_canceled_cb) {
@@ skipping 64 matching lines @@
   DCHECK(success);
 }
 
 void CancelableTaskTracker::Untrack(TaskId id) {
   DCHECK(sequence_checker_.CalledOnValidSequence());
   size_t num = task_flags_.erase(id);
   DCHECK_EQ(1u, num);
 }
 
 }  // namespace base