Implement PostDelayedTaskAt for guaranteed timer ordering

components/scheduler/renderer/renderer_scheduler_impl.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_SCHEDULER_RENDERER_RENDERER_SCHEDULER_IMPL_H_
 #define COMPONENTS_SCHEDULER_RENDERER_RENDERER_SCHEDULER_IMPL_H_
 
 #include "base/atomicops.h"
 #include "base/synchronization/lock.h"
 #include "components/scheduler/child/idle_helper.h"
@@ skipping 12 matching lines @@
 namespace scheduler {
 
 class SCHEDULER_EXPORT RendererSchedulerImpl : public RendererScheduler,
                                                public IdleHelper::Delegate {
  public:
   RendererSchedulerImpl(
       scoped_refptr<NestableSingleThreadTaskRunner> main_task_runner);
   ~RendererSchedulerImpl() override;
 
   // RendererScheduler implementation:
-  scoped_refptr<base::SingleThreadTaskRunner> DefaultTaskRunner() override;
+  scoped_refptr<TaskQueue> DefaultTaskRunner() override;
   scoped_refptr<SingleThreadIdleTaskRunner> IdleTaskRunner() override;
   scoped_refptr<base::SingleThreadTaskRunner> CompositorTaskRunner() override;
   scoped_refptr<base::SingleThreadTaskRunner> LoadingTaskRunner() override;
-  scoped_refptr<base::SingleThreadTaskRunner> TimerTaskRunner() override;
+  scoped_refptr<TaskQueue> TimerTaskRunner() override;
   void WillBeginFrame(const cc::BeginFrameArgs& args) override;
   void BeginFrameNotExpectedSoon() override;
   void DidCommitFrameToCompositor() override;
   void DidHandleInputEventOnCompositorThread(
       const blink::WebInputEvent& web_input_event,
       InputEventState event_state) override;
   void DidHandleInputEventOnMainThread(
       const blink::WebInputEvent& web_input_event) override;
   void DidAnimateForInputOnCompositorThread() override;
   void OnRendererHidden() override;
@@ skipping 144 matching lines @@
   // Returns true if there has been at least one idle period in the last
   // |kIdlePeriodStarvationThresholdMillis|.
   bool HadAnIdlePeriodRecently(base::TimeTicks now) const;
 
   SchedulerHelper helper_;
   IdleHelper idle_helper_;
 
   const scoped_refptr<base::SingleThreadTaskRunner> control_task_runner_;
   const scoped_refptr<base::SingleThreadTaskRunner> compositor_task_runner_;
   const scoped_refptr<base::SingleThreadTaskRunner> loading_task_runner_;
-  const scoped_refptr<base::SingleThreadTaskRunner> timer_task_runner_;
+  const scoped_refptr<TaskQueue> timer_task_runner_;
 
   base::Closure update_policy_closure_;
   DeadlineTaskRunner delayed_update_policy_runner_;
   CancelableClosureHolder end_renderer_hidden_idle_period_closure_;
 
   // We have decided to improve thread safety at the cost of some boilerplate
   // (the accessors) for the following data members.
 
   struct MainThreadOnly {
     MainThreadOnly();
@@ skipping 68 matching lines @@
 
   PollableThreadSafeFlag policy_may_need_update_;
   base::WeakPtrFactory<RendererSchedulerImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RendererSchedulerImpl);
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_RENDERER_RENDERER_SCHEDULER_IMPL_H_