[scheduler] Teach scheduler about audio state

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

 // 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.
 
 #ifndef THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_RENDERER_THROTTLING_HELPER_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_RENDERER_THROTTLING_HELPER_H_
 
 #include <set>
 #include <unordered_map>
 
@@ skipping 142 matching lines @@
   // becomes zero then |task_queue| is unthrottled.  If the refcount was already
   // zero this function does nothing.
   void DecreaseThrottleRefCount(TaskQueue* task_queue);
 
   // Removes |task_queue| from |queue_details| and from appropriate budget pool.
   void UnregisterTaskQueue(TaskQueue* task_queue);
 
   // 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();
 
   const ThrottledTimeDomain* time_domain() const { return time_domain_.get(); }
 
   static base::TimeTicks AlignedThrottledRunTime(
       base::TimeTicks unthrottled_runtime);
 
   const scoped_refptr<TaskQueue>& task_runner() const { return task_runner_; }
@@ skipping 46 matching lines @@
       base::TimeTicks now,
       TaskQueue* queue,
       base::Optional<base::TimeTicks> next_possible_run_time);
 
   // Return next possible time when queue is allowed to run in accordance
   // with throttling policy.
   base::TimeTicks GetNextAllowedRunTime(base::TimeTicks now, TaskQueue* queue);
 
   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_;
   RendererSchedulerImpl* renderer_scheduler_;  // NOT OWNED
   base::TickClock* tick_clock_;                // NOT OWNED
   const char* tracing_category_;               // NOT OWNED
   std::unique_ptr<ThrottledTimeDomain> time_domain_;
 
   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_;
 
   base::WeakPtrFactory<TaskQueueThrottler> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskQueueThrottler);
 };
 
 }  // namespace scheduler
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_RENDERER_THROTTLING_HELPER_H_