[scheduler] Implement time-based cpu throttling.

third_party/WebKit/Source/platform/scheduler/base/time_domain.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_BASE_TIME_DOMAIN_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_TIME_DOMAIN_H_
 
 #include <map>
 
 #include "base/callback.h"
@@ skipping 28 matching lines @@
 // The clock itself is provided by subclasses of the TimeDomain and it may be
 // the real wall clock or a synthetic (virtual) time base.
 class BLINK_PLATFORM_EXPORT TimeDomain {
  public:
   class BLINK_PLATFORM_EXPORT Observer {
    public:
     virtual ~Observer() {}
 
     // Called when an empty TaskQueue registered with this TimeDomain has a task
     // enqueued.
-    virtual void OnTimeDomainHasImmediateWork() = 0;
+    // |task_queue| - task queue which has immediate work scheduled.
+    virtual void OnTimeDomainHasImmediateWork(TaskQueue* task_queue) = 0;
 
     // Called when a TaskQueue registered with this TimeDomain has a delayed
     // task enqueued.
-    virtual void OnTimeDomainHasDelayedWork() = 0;
+    // |task_queue| - task queue which has delayed work scheduled.
+    virtual void OnTimeDomainHasDelayedWork(TaskQueue* task_queue) = 0;
   };
 
   explicit TimeDomain(Observer* observer);
   virtual ~TimeDomain();
 
   // Returns a LazyNow that evaluate this TimeDomain's Now.  Can be called from
   // any thread.
   // TODO(alexclarke): Make this main thread only.
   virtual LazyNow CreateLazyNow() const = 0;
 
@@ skipping 11 matching lines @@
   // runtime for the next one and it returns true.  Returns false otherwise.
   bool NextScheduledRunTime(base::TimeTicks* out_time) const;
 
  protected:
   friend class internal::TaskQueueImpl;
   friend class TaskQueueManager;
 
   void AsValueInto(base::trace_event::TracedValue* state) const;
 
   // Migrates |queue| from this time domain to |destination_time_domain|.
+  // Main-thread only.
   void MigrateQueue(internal::TaskQueueImpl* queue,
                     TimeDomain* destination_time_domain);
 
   // If there is a scheduled delayed task, |out_task_queue| is set to the queue
   // the next task was posted to and it returns true.  Returns false otherwise.
   bool NextScheduledTaskQueue(TaskQueue** out_task_queue) const;
 
   // Adds |queue| to the set of task queues that UpdateWorkQueues calls
   // UpdateWorkQueue on.
   void RegisterAsUpdatableTaskQueue(internal::TaskQueueImpl* queue);
@@ skipping 69 matching lines @@
 
   base::ThreadChecker main_thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(TimeDomain);
 };
 
 }  // namespace scheduler
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_TIME_DOMAIN_H_