Pass Callback by value on PostTaskAndReply family

base/threading/post_task_and_reply_impl.cc

 // Copyright (c) 2011 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/threading/post_task_and_reply_impl.h"
 
 #include "base/bind.h"
-#include "base/callback.h"
 #include "base/debug/leak_annotations.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/sequence_checker.h"
 #include "base/sequenced_task_runner.h"
 #include "base/threading/sequenced_task_runner_handle.h"
 
 namespace base {
 
 namespace {
 
 // This relay class remembers the sequence that it was created on, and ensures
 // that both the |task| and |reply| Closures are deleted on this same sequence.
 // Also, |task| is guaranteed to be deleted before |reply| is run or deleted.
 //
 // If RunReplyAndSelfDestruct() doesn't run because the originating execution
 // context is no longer available, then the |task| and |reply| Closures are
 // leaked. Leaking is considered preferable to having a thread-safetey
 // violations caused by invoking the Closure destructor on the wrong sequence.
 class PostTaskAndReplyRelay {
  public:
   PostTaskAndReplyRelay(const tracked_objects::Location& from_here,
-                        const Closure& task,
-                        const Closure& reply)
+                        Closure task,
+                        Closure reply)
       : sequence_checker_(),
         from_here_(from_here),
         origin_task_runner_(SequencedTaskRunnerHandle::Get()),
-        reply_(reply),
-        task_(task) {}
+        reply_(std::move(reply)),
+        task_(std::move(task)) {}

[gab, 2017/02/07 15:46:08]

#include <utility>

[tzik, 2017/02/08 01:39:32]

Done.

 
   ~PostTaskAndReplyRelay() {
     DCHECK(sequence_checker_.CalledOnValidSequence());
     task_.Reset();
     reply_.Reset();
   }
 
   void RunTaskAndPostReply() {
     task_.Run();
     origin_task_runner_->PostTask(
@@ skipping 22 matching lines @@
   Closure reply_;
   Closure task_;
 };
 
 }  // namespace
 
 namespace internal {
 
 bool PostTaskAndReplyImpl::PostTaskAndReply(
     const tracked_objects::Location& from_here,
-    const Closure& task,
-    const Closure& reply) {
+    Closure task,
+    Closure reply) {
   DCHECK(!task.is_null()) << from_here.ToString();
   DCHECK(!reply.is_null()) << from_here.ToString();
   PostTaskAndReplyRelay* relay =
-      new PostTaskAndReplyRelay(from_here, task, reply);
+      new PostTaskAndReplyRelay(from_here, std::move(task), std::move(reply));
   // PostTaskAndReplyRelay self-destructs after executing |reply|. On the flip
   // side though, it is intentionally leaked if the |task| doesn't complete
   // before the origin sequence stops executing tasks. Annotate |relay| as leaky
   // to avoid having to suppress every callsite which happens to flakily trigger
   // this race.
   ANNOTATE_LEAKING_OBJECT_PTR(relay);
   if (!PostTask(from_here, Bind(&PostTaskAndReplyRelay::RunTaskAndPostReply,
                                 Unretained(relay)))) {
     delete relay;
     return false;
   }
 
   return true;
 }
 
 }  // namespace internal
 
 }  // namespace base