[Android] Suspend shared timers for hidden renderers

components/scheduler/renderer/renderer_scheduler_impl.h

Index: components/scheduler/renderer/renderer_scheduler_impl.h
diff --git a/components/scheduler/renderer/renderer_scheduler_impl.h b/components/scheduler/renderer/renderer_scheduler_impl.h
index 14693460eba115a9d9d1438d7e528d1c0f75fb48..57b6a2bd4e3b5c262e8018d0b6c0e22455a1cc41 100644
--- a/components/scheduler/renderer/renderer_scheduler_impl.h
+++ b/components/scheduler/renderer/renderer_scheduler_impl.h
@@ -47,6 +47,8 @@ class SCHEDULER_EXPORT RendererSchedulerImpl : public RendererScheduler,
   void DidAnimateForInputOnCompositorThread() override;
   void OnRendererHidden() override;
   void OnRendererVisible() override;
+  void OnRendererBackgrounded() override;
+  void OnRendererForegrounded() override;
   void OnPageLoadStarted() override;
   bool IsHighPriorityWorkAnticipated() override;
   bool ShouldYieldForHighPriorityWork() override;
@@ -105,6 +107,9 @@ class SCHEDULER_EXPORT RendererSchedulerImpl : public RendererScheduler,
 
   void EndIdlePeriod();
 
+  void SuspendTimerQueueWhenBackgrounded();
+  void ResumeTimerQueueWhenForegrounded();
+
   // Returns the serialized scheduler state for tracing.
   scoped_refptr<base::trace_event::ConvertableToTraceFormat> AsValue(
       base::TimeTicks optional_now) const;
@@ -133,6 +138,14 @@ class SCHEDULER_EXPORT RendererSchedulerImpl : public RendererScheduler,
   // user gestures.
   static const int kIdlePeriodStarvationThresholdMillis = 10000;
 
+#if defined(OS_ANDROID)
+  // The amount of time to wait after suspending shared timers after the
+  // renderer has been backgrounded.
+  static const int kSuspendTimersWhenBackgroundedDelayMillis = 5 * 60 * 1000;

[Sami, 2015/08/28 14:15:01]

Just thinking ahead to testing this, perhaps it would be better to have a
boolean enable that we can call where the scheduler is created? That way the
tests can make sure this works on regardless of the platform they're running on.

[jdduke (slow), 2015/08/31 18:36:08]

Done.

+#else
+  static const int kSuspendTimersWhenBackgroundedDelayMillis = -1;
+#endif
+
   // Schedules an immediate PolicyUpdate, if there isn't one already pending and
   // sets |policy_may_need_update_|. Note |any_thread_lock_| must be
   // locked.
@@ -193,6 +206,7 @@ class SCHEDULER_EXPORT RendererSchedulerImpl : public RendererScheduler,
   base::Closure update_policy_closure_;
   DeadlineTaskRunner delayed_update_policy_runner_;
   CancelableClosureHolder end_renderer_hidden_idle_period_closure_;
+  CancelableClosureHolder suspend_timers_when_backgrounded_closure_;
 
   // We have decided to improve thread safety at the cost of some boilerplate
   // (the accessors) for the following data members.
@@ -209,6 +223,8 @@ class SCHEDULER_EXPORT RendererSchedulerImpl : public RendererScheduler,
     base::TimeDelta expected_short_idle_period_duration_;
     int timer_queue_suspend_count_;  // TIMER_TASK_QUEUE suspended if non-zero.
     bool renderer_hidden_;
+    bool renderer_backgrounded_;
+    bool timer_queue_suspended_for_backgrounded_renderer_;
     bool was_shutdown_;
   };