[scheduler] Add options to TaskQueue::InsertFence

third_party/WebKit/Source/platform/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 "platform/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 "platform/scheduler/base/real_time_domain.h"
@@ skipping 29 matching lines @@
       weak_factory_(this) {
   weak_idle_helper_ptr_ = weak_factory_.GetWeakPtr();
   enable_next_long_idle_period_closure_.Reset(
       base::Bind(&IdleHelper::EnableLongIdlePeriod, weak_idle_helper_ptr_));
   on_idle_task_posted_closure_.Reset(base::Bind(
       &IdleHelper::OnIdleTaskPostedOnMainThread, weak_idle_helper_ptr_));
 
   idle_task_runner_ = make_scoped_refptr(
       new SingleThreadIdleTaskRunner(idle_queue_, this, tracing_category));
 
-  idle_queue_->SetQueueEnabled(false);
+  idle_queue_->InsertFence(TaskQueue::InsertFencePosition::BEGINNING_OF_TIME);

[alex clarke (OOO till 29th), 2016/11/25 16:20:49]

Please add a comment explaining this blocks any idle tasks from running.

[altimin, 2016/11/25 16:59:25]

Done.

   idle_queue_->SetQueuePriority(TaskQueue::BEST_EFFORT_PRIORITY);
 
   helper_->AddTaskObserver(this);
 }
 
 IdleHelper::~IdleHelper() {
   Shutdown();
 }
 
 void IdleHelper::Shutdown() {
@@ skipping 116 matching lines @@
   if (idle_period_duration <
       base::TimeDelta::FromMilliseconds(kMinimumIdlePeriodDurationMillis)) {
     TRACE_EVENT1(disabled_by_default_tracing_category_,
                  "NotStartingIdlePeriodBecauseDeadlineIsTooClose",
                  "idle_period_duration_ms",
                  idle_period_duration.InMillisecondsF());
     return;
   }
 
   TRACE_EVENT0(disabled_by_default_tracing_category_, "StartIdlePeriod");
-  idle_queue_->SetQueueEnabled(true);
   // Use a fence to make sure any idle tasks posted after this point do not run
-  // until the next idle period.
-  idle_queue_->InsertFence();
+  // until the next idle period and unblock existing tasks.
+  idle_queue_->InsertFence(TaskQueue::InsertFencePosition::NOW);
 
   state_.UpdateState(new_state, idle_period_deadline, now);
 }
 
 void IdleHelper::EndIdlePeriod() {
   if (is_shutdown_)
     return;
 
   helper_->CheckOnValidThread();
   TRACE_EVENT0(disabled_by_default_tracing_category_, "EndIdlePeriod");
 
   enable_next_long_idle_period_closure_.Cancel();
   on_idle_task_posted_closure_.Cancel();
 
   // If we weren't already within an idle period then early-out.
   if (!IsInIdlePeriod(state_.idle_period_state()))
     return;
 
-  idle_queue_->SetQueueEnabled(false);
+  idle_queue_->InsertFence(TaskQueue::InsertFencePosition::BEGINNING_OF_TIME);

[alex clarke (OOO till 29th), 2016/11/25 16:20:49]

Please add a comment explaining this blocks any idle tasks from running.

[altimin, 2016/11/25 16:59:26]

Done.

   state_.UpdateState(IdlePeriodState::NOT_IN_IDLE_PERIOD, base::TimeTicks(),
                      base::TimeTicks());
 }
 
 void IdleHelper::WillProcessTask(const base::PendingTask& pending_task) {
   DCHECK(!is_shutdown_);
 }
 
 void IdleHelper::DidProcessTask(const base::PendingTask& pending_task) {
   helper_->CheckOnValidThread();
@@ skipping 273 matching lines @@
     case IdlePeriodState::IN_LONG_IDLE_PERIOD_PAUSED:
       return "in_long_idle_period_paused";
     default:
       NOTREACHED();
       return nullptr;
   }
 }
 
 }  // namespace scheduler
 }  // namespace blink