Remove worker pool names from TaskScheduler.TaskLatency.* histograms.

base/task_scheduler/task_tracker.h

 // Copyright 2016 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 BASE_TASK_SCHEDULER_TASK_TRACKER_H_
 #define BASE_TASK_SCHEDULER_TASK_TRACKER_H_
 
 #include <memory>
 
 #include "base/atomicops.h"
 #include "base/base_export.h"
 #include "base/callback_forward.h"
 #include "base/macros.h"
 #include "base/metrics/histogram_base.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/task_scheduler/scheduler_lock.h"
 #include "base/task_scheduler/sequence.h"
 #include "base/task_scheduler/task.h"
 #include "base/task_scheduler/task_traits.h"
 
 namespace base {
 
 class ConditionVariable;
+class HistogramBase;
 class SequenceToken;
 
 namespace internal {
 
 // All tasks go through the scheduler's TaskTracker when they are posted and
-// when they are executed. The TaskTracker enforces shutdown semantics and takes
-// care of tracing and profiling. This class is thread-safe.
+// when they are executed. The TaskTracker sets up the environment to run tasks,
+// enforces shutdown semantics, records metrics, and takes care of tracing and
+// profiling. This class is thread-safe.
 class BASE_EXPORT TaskTracker {
  public:
   TaskTracker();
   ~TaskTracker();
 
   // Synchronously shuts down the scheduler. Once this is called, only tasks
   // posted with the BLOCK_SHUTDOWN behavior will be run. Returns when:
   // - All SKIP_ON_SHUTDOWN tasks that were already running have completed their
   //   execution.
   // - All posted BLOCK_SHUTDOWN tasks have completed their execution.
@@ skipping 58 matching lines @@
   void AfterRunTask(TaskShutdownBehavior shutdown_behavior);
 
   // Called when the number of tasks blocking shutdown becomes zero after
   // shutdown has started.
   void OnBlockingShutdownTasksComplete();
 
   // Decrements the number of pending undelayed tasks and signals |flush_cv_| if
   // it reaches zero.
   void DecrementNumPendingUndelayedTasks();
 
+  // Records the TaskScheduler.TaskLatency.[task priority].[may block] histogram
+  // for |task|.
+  void RecordTaskLatencyHistogram(Task* task);
+
   // Number of tasks blocking shutdown and boolean indicating whether shutdown
   // has started.
   const std::unique_ptr<State> state_;
 
   // Number of undelayed tasks that haven't completed their execution. Is
   // incremented and decremented without a barrier. When it reaches zero,
   // |flush_lock_| is acquired (forcing memory synchronization) and |flush_cv_|
   // is signaled.
   subtle::Atomic32 num_pending_undelayed_tasks_ = 0;
 
   // Lock associated with |flush_cv_|. Partially synchronizes access to
   // |num_pending_undelayed_tasks_|. Full synchronization isn't needed because
   // it's atomic, but synchronization is needed to coordinate waking and
   // sleeping at the right time.
   mutable SchedulerLock flush_lock_;
 
   // Signaled when |num_pending_undelayed_tasks_| is zero or when shutdown
   // completes.
   const std::unique_ptr<ConditionVariable> flush_cv_;
 
   // Synchronizes access to shutdown related members below.
   mutable SchedulerLock shutdown_lock_;
 
   // Event instantiated when shutdown starts and signaled when shutdown
   // completes.
   std::unique_ptr<WaitableEvent> shutdown_event_;
 
+  // TaskScheduler.TaskLatency.[task priority].[may block] histograms. The first
+  // index is a TaskPriority. The second index is 0 for non-blocking tasks, 1
+  // for blocking tasks. Intentionally leaked.
+  HistogramBase* const
+      task_latency_histograms_[static_cast<int>(TaskPriority::HIGHEST) + 1][2];
+
   // Number of BLOCK_SHUTDOWN tasks posted during shutdown.
   HistogramBase::Sample num_block_shutdown_tasks_posted_during_shutdown_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(TaskTracker);
 };
 
 }  // namespace internal
 }  // namespace base
 
 #endif  // BASE_TASK_SCHEDULER_TASK_TRACKER_H_