TaskScheduler: Remove base/task_scheduler/utils.h/.cc

base/task_scheduler/scheduler_thread_pool.h

Index: base/task_scheduler/scheduler_thread_pool.h
diff --git a/base/task_scheduler/scheduler_thread_pool.h b/base/task_scheduler/scheduler_thread_pool.h
index 7afdd990854e155e009fa6a50e9f330de49305b1..2451474d297209912dfae6a491731871a7e59e49 100644
--- a/base/task_scheduler/scheduler_thread_pool.h
+++ b/base/task_scheduler/scheduler_thread_pool.h
@@ -5,128 +5,48 @@
 #ifndef BASE_TASK_SCHEDULER_SCHEDULER_THREAD_POOL_H_
 #define BASE_TASK_SCHEDULER_SCHEDULER_THREAD_POOL_H_
 
-#include <stddef.h>
-
 #include <memory>
-#include <vector>
 
 #include "base/base_export.h"
-#include "base/callback.h"
-#include "base/macros.h"
 #include "base/memory/ref_counted.h"
-#include "base/synchronization/condition_variable.h"
 #include "base/task_runner.h"
-#include "base/task_scheduler/priority_queue.h"
-#include "base/task_scheduler/scheduler_lock.h"
-#include "base/task_scheduler/scheduler_task_executor.h"
-#include "base/task_scheduler/scheduler_worker_thread.h"
-#include "base/task_scheduler/scheduler_worker_thread_stack.h"
 #include "base/task_scheduler/sequence.h"
 #include "base/task_scheduler/task.h"
 #include "base/task_scheduler/task_traits.h"
-#include "base/threading/platform_thread.h"
 
 namespace base {
 namespace internal {
 
-class DelayedTaskManager;
 struct SequenceSortKey;
-class TaskTracker;
 
-// A pool of threads that run Tasks. This class is thread-safe.
-class BASE_EXPORT SchedulerThreadPool : public SchedulerTaskExecutor {
+// Interface for a thread pool.
+class BASE_EXPORT SchedulerThreadPool {
  public:
-  // Callback invoked when a Sequence isn't empty after a worker thread pops a
-  // Task from it.
-  using EnqueueSequenceCallback = Callback<void(scoped_refptr<Sequence>)>;
-
-  // Destroying a SchedulerThreadPool returned by CreateThreadPool() is not
-  // allowed in production; it is always leaked. In tests, it can only be
-  // destroyed after JoinForTesting() has returned.
-  ~SchedulerThreadPool() override;
-
-  // Creates a SchedulerThreadPool with up to |max_threads| threads of priority
-  // |thread_priority|. |enqueue_sequence_callback| will be invoked after a
-  // thread of this thread pool tries to run a Task. |task_tracker| is used to
-  // handle shutdown behavior of Tasks. |delayed_task_manager| handles Tasks
-  // posted with a delay. Returns nullptr on failure to create a thread pool
-  // with at least one thread.
-  static std::unique_ptr<SchedulerThreadPool> CreateThreadPool(
-      ThreadPriority thread_priority,
-      size_t max_threads,
-      const EnqueueSequenceCallback& enqueue_sequence_callback,
-      TaskTracker* task_tracker,
-      DelayedTaskManager* delayed_task_manager);
+  virtual ~SchedulerThreadPool() = default;
 
   // Returns a TaskRunner whose PostTask invocations will result in scheduling
   // Tasks with |traits| and |execution_mode| in this thread pool.
-  scoped_refptr<TaskRunner> CreateTaskRunnerWithTraits(
+  virtual scoped_refptr<TaskRunner> CreateTaskRunnerWithTraits(
       const TaskTraits& traits,
-      ExecutionMode execution_mode);
+      ExecutionMode execution_mode) = 0;
 
   // Inserts |sequence| into this thread pool's shared priority queue with
   // |sequence_sort_key|. Must only be called from a worker thread to put
   // |sequence| back into a PriorityQueue after running a Task from it. The
   // worker thread doesn't have to belong to this thread pool.

[gab, 2016/04/26 22:00:56]

Actually this comment is also a bit outdated. Probably worth revisiting these
comments to make sure they match the new generic interface and situation.

-  void EnqueueSequence(scoped_refptr<Sequence> sequence,
-                       const SequenceSortKey& sequence_sort_key);
-
-  // Waits until all threads are idle.
-  void WaitForAllWorkerThreadsIdleForTesting();
-
-  // Joins all threads of this thread pool. Tasks that are already running are
-  // allowed to complete their execution. This can only be called once.
-  void JoinForTesting();
-
-  // SchedulerTaskExecutor:
-  void PostTaskWithSequence(std::unique_ptr<Task> task,
-                            scoped_refptr<Sequence> sequence) override;
-
- private:
-  class SchedulerWorkerThreadDelegateImpl;
-
-  SchedulerThreadPool(const EnqueueSequenceCallback& enqueue_sequence_callback,
-                      TaskTracker* task_tracker,
-                      DelayedTaskManager* delayed_task_manager);
-
-  bool Initialize(ThreadPriority thread_priority, size_t max_threads);
-
-  // Wakes up the last thread from this thread pool to go idle, if any.
-  void WakeUpOneThread();
-
-  // Adds |worker_thread| to |idle_worker_threads_stack_|.
-  void AddToIdleWorkerThreadsStack(SchedulerWorkerThread* worker_thread);
-
-  // PriorityQueue from which all threads of this thread pool get work.
-  PriorityQueue shared_priority_queue_;
-
-  // All worker threads owned by this thread pool. Only modified during
-  // initialization of the thread pool.
-  std::vector<std::unique_ptr<SchedulerWorkerThread>> worker_threads_;
-
-  // Synchronizes access to |idle_worker_threads_stack_| and
-  // |idle_worker_threads_stack_cv_for_testing_|. Has |shared_priority_queue_|'s
-  // lock as its predecessor so that a thread can be pushed to
-  // |idle_worker_threads_stack_| within the scope of a Transaction (more
-  // details in GetWork()).
-  SchedulerLock idle_worker_threads_stack_lock_;
-
-  // Stack of idle worker threads.
-  SchedulerWorkerThreadStack idle_worker_threads_stack_;
-
-  // Signaled when all worker threads become idle.
-  std::unique_ptr<ConditionVariable> idle_worker_threads_stack_cv_for_testing_;
-
-  // Signaled once JoinForTesting() has returned.
-  WaitableEvent join_for_testing_returned_;
-
-  // Delegate for all worker threads in this pool.
-  std::unique_ptr<SchedulerWorkerThread::Delegate> worker_thread_delegate_;
-
-  TaskTracker* const task_tracker_;
-  DelayedTaskManager* const delayed_task_manager_;
-
-  DISALLOW_COPY_AND_ASSIGN(SchedulerThreadPool);
+  virtual void ReEnqueueSequence(scoped_refptr<Sequence> sequence,
+                                 const SequenceSortKey& sequence_sort_key) = 0;
+
+  // Posts |task| to be executed as part of |sequence|.  Returns true if |task|
+  // is posted.
+  virtual bool PostTaskWithSequence(std::unique_ptr<Task> task,
+                                    scoped_refptr<Sequence> sequence) = 0;
+
+  // Posts |task| to be executed by this thread pool as part of |sequence|. The
+  // scheduler's TaskTracker must have allowed |task| to be posted before this

[gab, 2016/04/26 21:50:05]

Just realized while doing a local merge that this still mentions "TaskTracker"
although the generic interface doesn't know about it. Can we re-structure the
comments to avoid that?

+  // is called. This must only be called after |task|'s delayed run time.
+  virtual void PostTaskWithSequenceNow(std::unique_ptr<Task> task,
+                                       scoped_refptr<Sequence> sequence) = 0;
 };
 
 }  // namespace internal