Replace Closure in TaskRunner::PostTask with OneShotCallback

base/task_scheduler/scheduler_worker.cc

Index: base/task_scheduler/scheduler_worker.cc
diff --git a/base/task_scheduler/scheduler_worker.cc b/base/task_scheduler/scheduler_worker.cc
index 2bed780826e1e3b09a3bf2622455da4e54db0593..ec7f0bec789d116d01c186e815173be8a8cf8ac5 100644
--- a/base/task_scheduler/scheduler_worker.cc
+++ b/base/task_scheduler/scheduler_worker.cc
@@ -70,7 +70,7 @@ class SchedulerWorker::Thread : public PlatformThread::Delegate {
         continue;
       }
 
-      const Task* task = sequence->PeekTask();
+      Task* task = sequence->PeekTask();
       const TimeTicks start_time = TimeTicks::Now();
       if (outer_->task_tracker_->RunTask(task, sequence->token()))
         outer_->delegate_->DidRunTask(task, start_time - task->sequenced_time);