Move and rename TaskTimeTracker to public interface exposed to WebThread, use in WebPerf Agent.

third_party/WebKit/Source/platform/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 THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_MANAGER_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_MANAGER_H_
 
 #include <map>
 
 #include "base/atomic_sequence_num.h"
@@ skipping 65 matching lines @@
   void MaybeScheduleDelayedWork(const tracked_objects::Location& from_here,
                                 base::TimeTicks now,
                                 base::TimeDelta delay);
 
   // Set the number of tasks executed in a single invocation of the task queue
   // manager. Increasing the batch size can reduce the overhead of yielding
   // back to the main message loop -- at the cost of potentially delaying other
   // tasks posted to the main loop. The batch size is 1 by default.
   void SetWorkBatchSize(int work_batch_size);
 
-  // When given a non-null TaskTimeTracker, the TaskQueueManager calls its
-  // ReportTaskTime method for every top level task. The task_time_tracker must
-  // outlive this object, or be removed via SetTaskTimeTracker(nullptr).
-  void SetTaskTimeTracker(TaskTimeTracker* task_time_tracker) {
-    task_time_tracker_ = task_time_tracker;
-  }
-
   // These functions can only be called on the same thread that the task queue
   // manager executes its tasks on.
   void AddTaskObserver(base::MessageLoop::TaskObserver* task_observer);
   void RemoveTaskObserver(base::MessageLoop::TaskObserver* task_observer);
+  void AddTaskTimeTracker(TaskTimeTracker* task_time_tracker);

[Sami, 2016/08/23 10:34:59]

naming bikeshed: Should we rename this to TaskTimeObserver for consistency?

[panicker, 2016/08/23 18:08:23]

Sure, I'm fine with that.
Although I'd prefer to make the naming change after addressing all other review
comments.

+  void RemoveTaskTimeTracker(TaskTimeTracker* task_time_tracker);
 
   // Returns true if any task from a monitored task queue was was run since the
   // last call to GetAndClearSystemIsQuiescentBit.
   bool GetAndClearSystemIsQuiescentBit();
 
   // Creates a task queue with the given |spec|.  Must be called on the thread
   // this class was created on.
   scoped_refptr<internal::TaskQueueImpl> NewTaskQueue(
       const TaskQueue::Spec& spec);
 
@@ skipping 134 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
+  base::ObserverList<TaskTimeTracker> task_time_trackers_;
 
   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
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_TASK_QUEUE_MANAGER_H_