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"
 #include "base/debug/task_annotator.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/pending_task.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
 #include "platform/scheduler/base/enqueue_order.h"
 #include "platform/scheduler/base/task_queue_impl.h"
 #include "platform/scheduler/base/task_queue_selector.h"
+#include "public/platform/WebThread.h"
 
 namespace base {
 class TickClock;
 
 namespace trace_event {
 class ConvertableToTraceFormat;
 class TracedValue;
 }  // namespace trace_event
 }  // namespace base
 
@@ skipping 52 matching lines @@
   // 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;
   }
 
+  void AddTaskTimeObserver(WebThread::TaskTimeObserver* task_time_observer) {
+    // FIX ME: Make this a list!
+    task_time_observer_ = task_time_observer;
+  }
+
+  void RemoveTaskTimeObserver(WebThread::TaskTimeObserver* task_time_observer) {
+    // FIX ME: Remove from list!
+    task_time_observer_ = nullptr;
+  }
+
   // 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);
 
   // 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
@@ skipping 139 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
+  WebThread::TaskTimeObserver* task_time_observer_;  // NOT OWNED

[Sami, 2016/08/19 14:44:56]

Could we define this interface here instead? In principle base/ things shouldn't
depend on core/ things since it creates a cyclic dependency.

Also, it feels like the observer should be on the TaskTimeTracker since I think
we'll also want to use it internally.

[panicker, 2016/08/19 18:06:50]

Could you clarify the base/-core/ issue here? Is public/platform/WebThread.h
considered "core" ?

BTW I first tried to repurpose the TaskTimeTracker interface
(platform/scheduler/base/task_time_tracker.h), but the issue was I couldn't find
a way to hook up the WebPerfAgent to it without making WebThread aware of it.
i.e. in WebPerfAgent if we did something like:
Platform::current()->currentThread()->addTaskTimeTracker(this);
then WebThread needs to be aware of TaskTimeTracker interface.

Instead we can switch the current TaskTimeTracker to merge with the
TaskTimeObserver that I just added (instead of the other way around).
Does that make sense?


 

 
   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_