content: Add task queue manager

base/task/task_queue_scheduler.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 BASE_TASK_TASK_QUEUE_SCHEDULER_H_
+#define BASE_TASK_TASK_QUEUE_SCHEDULER_H_
+
+#include <vector>
+
+#include "base/base_export.h"
+#include "base/basictypes.h"
+
+namespace base {
+class TaskQueue;
+
+class BASE_EXPORT TaskQueueScheduler {
+ public:
+  virtual ~TaskQueueScheduler() {}
+
+  // Called once to register the work queues to be scheduled. This function is
+  // called on the main thread.
+  virtual void RegisterWorkQueues(
+      const std::vector<const TaskQueue*>& work_queues) = 0;
+
+  // Called to choose the work queue from which the next task should be taken
+  // and run. Return true if |out_queue| indicates the queue to service or
+  // false to avoid running any task.
+  //
+  // This function is called on the main thread.
+  virtual bool ChooseWorkQueueToService(size_t* out_queue_index) = 0;
+};
+
+}  // namespace content
+
+#endif  // BASE_TASK_TASK_QUEUE_SCHEDULER_H_