Purge memory before suspending timer queues when backgrounded.

third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc

Index: third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc
diff --git a/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc b/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc
index cb4938dc6b74f1baa9047d51c1c9c05ee59111f0..1b51b3e8e6c8474468210c2a860dd9bcd0ae0b69 100644
--- a/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc
+++ b/third_party/WebKit/Source/platform/scheduler/renderer/renderer_scheduler_impl.cc
@@ -123,10 +123,6 @@ RendererSchedulerImpl::RendererSchedulerImpl(
   end_renderer_hidden_idle_period_closure_.Reset(base::Bind(
       &RendererSchedulerImpl::EndIdlePeriod, weak_factory_.GetWeakPtr()));
 
-  suspend_timers_when_backgrounded_closure_.Reset(
-      base::Bind(&RendererSchedulerImpl::SuspendTimerQueueWhenBackgrounded,
-                 weak_factory_.GetWeakPtr()));
-
   default_loading_task_runner_ =
       NewLoadingTaskRunner(TaskQueue::QueueType::DEFAULT_LOADING);
   default_timer_task_runner_ =
@@ -206,7 +202,6 @@ RendererSchedulerImpl::MainThreadOnly::MainThreadOnly(
       renderer_hidden(false),
       renderer_backgrounded(false),
       renderer_suspended(false),
-      timer_queue_suspension_when_backgrounded_enabled(false),
       timer_queue_suspended_when_backgrounded(false),
       was_shutdown(false),
       loading_tasks_seem_expensive(false),
@@ -500,17 +495,6 @@ void RendererSchedulerImpl::OnRendererBackgrounded() {
   base::TimeTicks now = tick_clock()->NowTicks();
   MainThreadOnly().foreground_main_thread_load_tracker.Pause(now);
   MainThreadOnly().background_main_thread_load_tracker.Resume(now);
-
-  if (!MainThreadOnly().timer_queue_suspension_when_backgrounded_enabled)
-    return;
-
-  suspend_timers_when_backgrounded_closure_.Cancel();
-  base::TimeDelta suspend_timers_when_backgrounded_delay =
-      base::TimeDelta::FromMilliseconds(
-          kSuspendTimersWhenBackgroundedDelayMillis);
-  control_task_runner_->PostDelayedTask(
-      FROM_HERE, suspend_timers_when_backgrounded_closure_.callback(),
-      suspend_timers_when_backgrounded_delay);
 }
 
 void RendererSchedulerImpl::OnRendererForegrounded() {
@@ -529,7 +513,6 @@ void RendererSchedulerImpl::OnRendererForegrounded() {
   MainThreadOnly().foreground_main_thread_load_tracker.Resume(now);
   MainThreadOnly().background_main_thread_load_tracker.Pause(now);
 
-  suspend_timers_when_backgrounded_closure_.Cancel();
   ResumeTimerQueueWhenForegroundedOrResumed();
 }
 
@@ -556,7 +539,6 @@ void RendererSchedulerImpl::SuspendRenderer() {
     return;
   if (!MainThreadOnly().renderer_backgrounded)
     return;
-  suspend_timers_when_backgrounded_closure_.Cancel();
 
   UMA_HISTOGRAM_COUNTS("PurgeAndSuspend.PendingTaskCount",
                        helper_.GetNumberOfPendingTasks());
@@ -573,7 +555,7 @@ void RendererSchedulerImpl::ResumeRenderer() {
     return;
   if (!MainThreadOnly().renderer_backgrounded)
     return;
-  suspend_timers_when_backgrounded_closure_.Cancel();
+
   MainThreadOnly().renderer_suspended = false;
   ResumeTimerQueueWhenForegroundedOrResumed();
 }
@@ -1333,12 +1315,6 @@ void RendererSchedulerImpl::ResumeTimerQueue() {
   ForceUpdatePolicy();
 }
 
-void RendererSchedulerImpl::SetTimerQueueSuspensionWhenBackgroundedEnabled(
-    bool enabled) {
-  // Note that this will only take effect for the next backgrounded signal.
-  MainThreadOnly().timer_queue_suspension_when_backgrounded_enabled = enabled;
-}
-
 std::unique_ptr<base::trace_event::ConvertableToTraceFormat>
 RendererSchedulerImpl::AsValue(base::TimeTicks optional_now) const {
   base::AutoLock lock(any_thread_lock_);
@@ -1413,8 +1389,6 @@ RendererSchedulerImpl::AsValueLocked(base::TimeTicks optional_now) const {
       MainThreadOnly().have_reported_blocking_intervention_since_navigation);
   state->SetBoolean("renderer_backgrounded",
                     MainThreadOnly().renderer_backgrounded);
-  state->SetBoolean("timer_queue_suspended_when_backgrounded",
-                    MainThreadOnly().timer_queue_suspended_when_backgrounded);
   state->SetInteger("timer_queue_suspend_count",
                     MainThreadOnly().timer_queue_suspend_count);
   state->SetDouble("now", (optional_now - base::TimeTicks()).InMillisecondsF());