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

chrome/browser/after_startup_task_utils.cc

Index: chrome/browser/after_startup_task_utils.cc
diff --git a/chrome/browser/after_startup_task_utils.cc b/chrome/browser/after_startup_task_utils.cc
index c5c29e8b8cb599f7305a2df9b0a82abce8dd1e7c..3f5e49033ed3bbdcf9ab1d67abdf804d56ad46e4 100644
--- a/chrome/browser/after_startup_task_utils.cc
+++ b/chrome/browser/after_startup_task_utils.cc
@@ -7,6 +7,7 @@
 #include <memory>
 #include <utility>
 
+#include "base/callback_helpers.h"
 #include "base/lazy_instance.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
@@ -34,13 +35,13 @@ namespace {
 struct AfterStartupTask {
   AfterStartupTask(const tracked_objects::Location& from_here,
                    const scoped_refptr<base::TaskRunner>& task_runner,
-                   const base::Closure& task)
-      : from_here(from_here), task_runner(task_runner), task(task) {}
+                   base::Closure task)
+      : from_here(from_here), task_runner(task_runner), task(std::move(task)) {}
   ~AfterStartupTask() {}
 
   const tracked_objects::Location from_here;
   const scoped_refptr<base::TaskRunner> task_runner;
-  const base::Closure task;
+  base::Closure task;
 };
 
 // The flag may be read on any thread, but must only be set on the UI thread.
@@ -60,7 +61,7 @@ bool IsBrowserStartupComplete() {
 void RunTask(std::unique_ptr<AfterStartupTask> queued_task) {
   // We're careful to delete the caller's |task| on the target runner's thread.
   DCHECK(queued_task->task_runner->RunsTasksOnCurrentThread());
-  queued_task->task.Run();
+  base::ResetAndReturn(&queued_task->task).Run();
 }
 
 void ScheduleTask(std::unique_ptr<AfterStartupTask> queued_task) {
@@ -202,10 +203,11 @@ AfterStartupTaskUtils::Runner::~Runner() = default;
 
 bool AfterStartupTaskUtils::Runner::PostDelayedTask(
     const tracked_objects::Location& from_here,
-    const base::Closure& task,
+    base::Closure task,
     base::TimeDelta delay) {
   DCHECK(delay.is_zero());
-  AfterStartupTaskUtils::PostTask(from_here, destination_runner_, task);
+  AfterStartupTaskUtils::PostTask(from_here, destination_runner_,
+                                  std::move(task));
   return true;
 }
 
@@ -221,14 +223,14 @@ void AfterStartupTaskUtils::StartMonitoringStartup() {
 void AfterStartupTaskUtils::PostTask(
     const tracked_objects::Location& from_here,
     const scoped_refptr<base::TaskRunner>& destination_runner,
-    const base::Closure& task) {
+    base::Closure task) {
   if (IsBrowserStartupComplete()) {
-    destination_runner->PostTask(from_here, task);
+    destination_runner->PostTask(from_here, std::move(task));
     return;
   }
 
   std::unique_ptr<AfterStartupTask> queued_task(
-      new AfterStartupTask(from_here, destination_runner, task));
+      new AfterStartupTask(from_here, destination_runner, std::move(task)));
   QueueTask(std::move(queued_task));
 }