POC: Instrument task time tracker

components/scheduler/base/task_queue_manager.h

 // Copyright 2014 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 CONTENT_RENDERER_SCHEDULER_BASE_TASK_QUEUE_MANAGER_H_
 #define CONTENT_RENDERER_SCHEDULER_BASE_TASK_QUEUE_MANAGER_H_
 
 #include <map>
 
 #include "base/atomic_sequence_num.h"
@@ skipping 20 matching lines @@
 
 namespace scheduler {
 namespace internal {
 class TaskQueueImpl;
 }  // namespace internal
 
 class LazyNow;
 class RealTimeDomain;
 class TimeDomain;
 class TaskQueueManagerDelegate;
+class TaskTimeTracker;
 
 // The task queue manager provides N task queues and a selector interface for
 // choosing which task queue to service next. Each task queue consists of two
 // sub queues:
 //
 // 1. Incoming task queue. Tasks that are posted get immediately appended here.
 //    When a task is appended into an empty incoming queue, the task manager
 //    work function (DoWork) is scheduled to run on the main task runner.
 //
 // 2. Work queue. If a work queue is empty when DoWork() is entered, tasks from
 //    the incoming task queue (if any) are moved here. The work queues are
 //    registered with the selector as input to the scheduling decision.
 //
 class SCHEDULER_EXPORT TaskQueueManager
     : public internal::TaskQueueSelector::Observer {
  public:
   // Create a task queue manager where |delegate| identifies the thread
   // on which where the tasks are  eventually run. Category strings must have
   // application lifetime (statics or literals). They may not include " chars.
   TaskQueueManager(scoped_refptr<TaskQueueManagerDelegate> delegate,
                    const char* tracing_category,
                    const char* disabled_by_default_tracing_category,
-                   const char* disabled_by_default_verbose_tracing_category);
+                   const char* disabled_by_default_verbose_tracing_category,
+                   TaskTimeTracker* task_time_tracker);
   ~TaskQueueManager() override;
 
   // Requests that a task to process work is posted on the main task runner.
   // These tasks are de-duplicated in two buckets: main-thread and all other
   // threads.  This distinction is done to reduce the overehead from locks, we
   // assume the main-thread path will be hot.
   void MaybeScheduleImmediateWork(const tracked_objects::Location& from_here);
 
   // Requests that a delayed task to process work is posted on the main task
   // runner. These delayed tasks are de-duplicated. Must be called on the thread
@@ skipping 158 matching lines @@
 
   // Protects |other_thread_pending_wakeups_|.
   mutable base::Lock other_thread_lock_;
   std::set<base::TimeTicks> other_thread_pending_wakeups_;
 
   int work_batch_size_;
   size_t task_count_;
 
   base::ObserverList<base::MessageLoop::TaskObserver> task_observers_;
 
+  TaskTimeTracker* task_time_tracker_;  // NOT OWNED
+  std::unique_ptr<base::TickClock> timer_;
+
   const char* tracing_category_;
   const char* disabled_by_default_tracing_category_;
   const char* disabled_by_default_verbose_tracing_category_;
 
   internal::TaskQueueImpl* currently_executing_task_queue_;  // NOT OWNED
 
   Observer* observer_;  // NOT OWNED
   scoped_refptr<DeletionSentinel> deletion_sentinel_;
   base::WeakPtrFactory<TaskQueueManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskQueueManager);
 };
 
 }  // namespace scheduler
 
 #endif  // CONTENT_RENDERER_SCHEDULER_BASE_TASK_QUEUE_MANAGER_H_