Add TaskScheduler.NumTasksBeforeDetach.[worker pool name] histogram.

base/task_scheduler/scheduler_worker_pool_impl.h

Index: base/task_scheduler/scheduler_worker_pool_impl.h
diff --git a/base/task_scheduler/scheduler_worker_pool_impl.h b/base/task_scheduler/scheduler_worker_pool_impl.h
index 94998bc7a77bf1809af01bb217a86bbd6050eb4c..d1f94e391b1d75e7d848f827b61aa5ca46b19096 100644
--- a/base/task_scheduler/scheduler_worker_pool_impl.h
+++ b/base/task_scheduler/scheduler_worker_pool_impl.h
@@ -94,6 +94,10 @@ class BASE_EXPORT SchedulerWorkerPoolImpl : public SchedulerWorkerPool {
                                scoped_refptr<Sequence> sequence,
                                SchedulerWorker* worker) override;
 
+  const HistogramBase* num_tasks_before_detach_histogram_for_testing() const {

[robliao, 2016/10/13 18:04:04]

Feel free to remove the _for_testing portion of this getting. I'll be
referencing them in the upcoming taskscheduler stats page change.

[fdoray, 2016/10/13 20:38:52]

Done.

+    return num_tasks_before_detach_histogram_;
+  }
+
   const HistogramBase* num_tasks_between_waits_histogram_for_testing() const {
     return num_tasks_between_waits_histogram_;
   }
@@ -185,6 +189,10 @@ class BASE_EXPORT SchedulerWorkerPoolImpl : public SchedulerWorkerPool {
   // leaked.
   HistogramBase* const detach_duration_histogram_;
 
+  // TaskScheduler.NumTasksBeforeDetach.[worker pool name] histogram.
+  // Intentionally leaked.
+  HistogramBase* const num_tasks_before_detach_histogram_;
+
   // TaskScheduler.NumTasksBetweenWaits.[worker pool name] histogram.
   // Intentionally leaked.
   HistogramBase* const num_tasks_between_waits_histogram_;