Add Lazy Creation and Thread Detachment Support in the Scheduler Worker Pool

base/task_scheduler/scheduler_worker_pool_params.h

Index: base/task_scheduler/scheduler_worker_pool_params.h
diff --git a/base/task_scheduler/scheduler_worker_pool_params.h b/base/task_scheduler/scheduler_worker_pool_params.h
index 229d335476903068211935392f9a804f0cec3c2c..e557736311e3fe10acd79c247bb15c291dd9df00 100644
--- a/base/task_scheduler/scheduler_worker_pool_params.h
+++ b/base/task_scheduler/scheduler_worker_pool_params.h
@@ -11,6 +11,9 @@
 #include "base/threading/platform_thread.h"
 
 namespace base {
+
+class TimeDelta;

[fdoray, 2016/07/20 14:15:44]

#include "base/time/time.h" given that there is a TimeDelta member?

[robliao, 2016/07/20 19:44:01]

The forward-decl still works here since we only need to know the size in the
constructor. Folks who include this should also include time.h as well since
they themselves will be using TimeDelta.

+
 namespace internal {
 
 class BASE_EXPORT SchedulerWorkerPoolParams final {
@@ -23,12 +26,15 @@ class BASE_EXPORT SchedulerWorkerPoolParams final {
   // Construct a worker pool parameter object that instructs a worker pool to
   // use the label |name| and create up to |max_threads| threads of priority
   // |thread_priority|. |io_restriction| indicates whether Tasks on the worker
-  // pool are allowed to make I/O calls.
+  // pool are allowed to make I/O calls. |suggested_reclaim_time| sets a
+  // suggestion on when to reclaim idle threads. The worker pool is free to
+  // ignore this value for performance or correctness reasons.
   SchedulerWorkerPoolParams(
       const std::string& name,
       ThreadPriority thread_priority,
       IORestriction io_restriction,
-      int max_threads);
+      int max_threads,
+      const TimeDelta& suggested_reclaim_time);
   SchedulerWorkerPoolParams(SchedulerWorkerPoolParams&& other);
   SchedulerWorkerPoolParams& operator=(SchedulerWorkerPoolParams&& other);
 
@@ -44,11 +50,17 @@ class BASE_EXPORT SchedulerWorkerPoolParams final {
   // Maximum number of threads in the pool.
   size_t max_threads() const { return max_threads_; }
 
+  // Suggested reclaim time for threads in the worker pool.
+  const TimeDelta& suggested_reclaim_time() const {
+    return suggested_reclaim_time_;
+  }
+
  private:
   std::string name_;
   ThreadPriority thread_priority_;
   IORestriction io_restriction_;
   size_t max_threads_;
+  TimeDelta suggested_reclaim_time_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerWorkerPoolParams);
 };