Introduce a SchedulerHelper in content/child/scheduler

content/child/scheduler/task_queue_manager.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 CONTENT_RENDERER_SCHEDULER_TASK_QUEUE_MANAGER_H_
 #define CONTENT_RENDERER_SCHEDULER_TASK_QUEUE_MANAGER_H_
 
 #include "base/atomic_sequence_num.h"
 #include "base/debug/task_annotator.h"
 #include "base/macros.h"
@@ skipping 55 matching lines @@
     MANUAL
   };
 
   // Create a task queue manager with |task_queue_count| task queues.
   // |main_task_runner| identifies the thread on which where the tasks are
   // eventually run. |selector| is used to choose which task queue to service.
   // It should outlive this class.
   TaskQueueManager(
       size_t task_queue_count,
       scoped_refptr<NestableSingleThreadTaskRunner> main_task_runner,
-      TaskQueueSelector* selector);
+      TaskQueueSelector* selector,
+      const char* disabled_by_default_tracing_category);

[rmcilroy, 2015/03/27 14:34:40]

and here

[alex clarke (OOO till 29th), 2015/03/27 16:09:17]

Done.

   ~TaskQueueManager();
 
   // Returns the task runner which targets the queue selected by |queue_index|.
   scoped_refptr<base::SingleThreadTaskRunner> TaskRunnerForQueue(
       size_t queue_index) const;
 
   // Sets the pump policy for the |queue_index| to |pump_policy|. By
   // default queues are created with AUTO_PUMP_POLICY.
   void SetPumpPolicy(size_t queue_index, PumpPolicy pump_policy);
 
@@ skipping 100 matching lines @@
   // The pending_dowork_count_ is only tracked on the main thread since that's
   // where re-entrant problems happen.
   int pending_dowork_count_;
 
   int work_batch_size_;
 
   scoped_refptr<cc::TestNowSource> time_source_;
 
   ObserverList<base::MessageLoop::TaskObserver> task_observers_;
 
+  const char* disabled_by_default_tracing_category_;
+
   base::WeakPtrFactory<TaskQueueManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskQueueManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_SCHEDULER_TASK_QUEUE_MANAGER_H_