Implement PostDelayedTaskAt for guaranteed timer ordering

components/scheduler/child/idle_helper.cc

 // Copyright 2015 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 "components/scheduler/child/idle_helper.h"
 
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "base/trace_event/trace_event_argument.h"
 #include "components/scheduler/child/scheduler_helper.h"
+#include "components/scheduler/child/task_queue.h"
 
 namespace scheduler {
 
 IdleHelper::IdleHelper(
     SchedulerHelper* helper,
     Delegate* delegate,
     size_t idle_queue_index,
     const char* tracing_category,
     const char* disabled_by_default_tracing_category,
     const char* idle_period_tracing_name,
@@ skipping 465 matching lines @@
       return "in_long_idle_period_with_max_deadline";
     case IdlePeriodState::IN_LONG_IDLE_PERIOD_PAUSED:
       return "in_long_idle_period_paused";
     default:
       NOTREACHED();
       return nullptr;
   }
 }
 
 }  // namespace scheduler