Replace Closure in TaskRunner::PostTask with OneShotCallback

base/deferred_sequenced_task_runner.h

Index: base/deferred_sequenced_task_runner.h
diff --git a/base/deferred_sequenced_task_runner.h b/base/deferred_sequenced_task_runner.h
index e5d57df5a0ba4ed095c4b6a71b66f56caf9fb14c..a731b0e66b7744a8f2b4fa60ede8acebb8aa54f9 100644
--- a/base/deferred_sequenced_task_runner.h
+++ b/base/deferred_sequenced_task_runner.h
@@ -28,13 +28,13 @@ class BASE_EXPORT DeferredSequencedTaskRunner : public SequencedTaskRunner {
 
   // TaskRunner implementation
   bool PostDelayedTask(const tracked_objects::Location& from_here,
-                       const Closure& task,
+                       OnceClosure task,
                        TimeDelta delay) override;
   bool RunsTasksOnCurrentThread() const override;
 
   // SequencedTaskRunner implementation
   bool PostNonNestableDelayedTask(const tracked_objects::Location& from_here,
-                                  const Closure& task,
+                                  OnceClosure task,
                                   TimeDelta delay) override;
 
   // Start the execution - posts all queued tasks to the target executor. The
@@ -46,11 +46,13 @@ class BASE_EXPORT DeferredSequencedTaskRunner : public SequencedTaskRunner {
  private:
   struct DeferredTask  {
     DeferredTask();
-    DeferredTask(const DeferredTask& other);
+    DeferredTask(DeferredTask&& other);
     ~DeferredTask();
 
+    DeferredTask& operator=(DeferredTask&& other);
+
     tracked_objects::Location posted_from;
-    Closure task;
+    mutable OnceClosure task;
     // The delay this task was initially posted with.
     TimeDelta delay;
     bool is_non_nestable;
@@ -60,7 +62,7 @@ class BASE_EXPORT DeferredSequencedTaskRunner : public SequencedTaskRunner {
 
   // Creates a |Task| object and adds it to |deferred_tasks_queue_|.
   void QueueDeferredTask(const tracked_objects::Location& from_here,
-                         const Closure& task,
+                         OnceClosure task,
                          TimeDelta delay,
                          bool is_non_nestable);