[scheduler] Teach scheduler about audio state

third_party/WebKit/Source/platform/scheduler/renderer/task_queue_throttler.h

Index: third_party/WebKit/Source/platform/scheduler/renderer/task_queue_throttler.h
diff --git a/third_party/WebKit/Source/platform/scheduler/renderer/task_queue_throttler.h b/third_party/WebKit/Source/platform/scheduler/renderer/task_queue_throttler.h
index 5b249c76f3fe12d1aa0ca0d09968a7c4cfd86c4a..83cfcbfd9e0401b169c82dc1a745eef558c9b612 100644
--- a/third_party/WebKit/Source/platform/scheduler/renderer/task_queue_throttler.h
+++ b/third_party/WebKit/Source/platform/scheduler/renderer/task_queue_throttler.h
@@ -160,6 +160,9 @@ class BLINK_PLATFORM_EXPORT TaskQueueThrottler : public TimeDomain::Observer {
   // Returns true if the |task_queue| is throttled.
   bool IsThrottled(TaskQueue* task_queue) const;
 
+  // Communicate audio state to TaskQueueThrottler.
+  void SetIsAudioActive(bool is_audio_active);

[Sami, 2016/09/29 13:36:07]

I don't think TaskQueueThrottler should know about audio. This feels more like a
RendererScheduler type of thing.

[altimin, 2016/09/29 16:29:43]

Done.

+
   // Tells the TaskQueueThrottler we're using virtual time, which disables all
   // throttling.
   void EnableVirtualTime();
@@ -226,6 +229,16 @@ class BLINK_PLATFORM_EXPORT TaskQueueThrottler : public TimeDomain::Observer {
 
   void MaybeDeleteQueueMetadata(TaskQueueMap::iterator it);
 
+  // Disable throttling for all queues, this setting takes precedence over
+  // all other throttling settings. Designed to be used when a global event
+  // disabling throttling happens (e.g. audio is playing).
+  void DisableThrottling();
+
+  // Enable back global throttling.
+  void EnableThrottling();
+
+  void UpdateGlobalThrottlingSetting();

[alex clarke (OOO till 29th), 2016/09/29 11:16:53]

Sami how do you feel about this vs UpdatePolicy? Maybe it's OK for this to be
separate but usually we'd have triggered a policy update to deal with state
changes.

[Sami, 2016/09/29 13:36:07]

Yeah I think we want to cause a policy update instead. I could see us needing
the audio state for setting task queue priorities etc. in the future.

[alex clarke (OOO till 29th), 2016/09/29 13:46:18]

Thinking about this more I'd suggest instead of adding DelayedSwitch we track
the last time audio was played in RendererSchedulerImpl::MainThreadOnly

Change |new_policy_duration| to be the min of last audio play time +
kThrottlingDelayAfterAudioIsPlayedInSeconds  and |expected_use_case_duration|.

SetIsAudioActive should update the last audio play time and call
MaybeUpdatePolicy.

[altimin, 2016/09/29 16:29:43]

Done.

+
   TaskQueueMap queue_details_;
   base::Callback<void(TaskQueue*)> forward_immediate_work_callback_;
   scoped_refptr<TaskQueue> task_runner_;
@@ -236,7 +249,9 @@ class BLINK_PLATFORM_EXPORT TaskQueueThrottler : public TimeDomain::Observer {
 
   CancelableClosureHolder pump_throttled_tasks_closure_;
   base::Optional<base::TimeTicks> pending_pump_throttled_tasks_runtime_;
+  bool is_throttling_disabled_;

[Sami, 2016/09/29 13:36:07]

Negative flags hurt my head -- how about allow_throttling_?

[altimin, 2016/09/29 16:29:43]

Done.

   bool virtual_time_;
+  bool is_audio_active_;
 
   std::unordered_map<TimeBudgetPool*, std::unique_ptr<TimeBudgetPool>>
       time_budget_pools_;