Introduce a SchedulerHelper in content/child/scheduler

content/child/scheduler/task_queue_selector_impl.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_RENDERER_TASK_QUEUE_SELECTOR_H_
-#define CONTENT_RENDERER_SCHEDULER_RENDERER_TASK_QUEUE_SELECTOR_H_
+#ifndef CONTENT_CHILD_SCHEDULER_TASK_QUEUE_SELECTOR_IMPL_H_
+#define CONTENT_CHILD_SCHEDULER_TASK_QUEUE_SELECTOR_IMPL_H_
 
 #include <set>
 
 #include "base/compiler_specific.h"
 #include "base/threading/thread_checker.h"
+#include "content/child/scheduler/task_queue_selector.h"
 #include "content/common/content_export.h"
-#include "content/renderer/scheduler/task_queue_selector.h"
 
 namespace content {
 
-// A RendererTaskQueueSelector is a TaskQueueSelector which is used by the
-// RendererScheduler to enable prioritization of particular task queues.
-class CONTENT_EXPORT RendererTaskQueueSelector
+// A TaskQueueSelectorImpl is a TaskQueueSelector which is used by the
+// SchedulerHelper to enable prioritization of particular task queues.
+class CONTENT_EXPORT TaskQueueSelectorImpl

[Sami, 2015/03/27 01:15:55]

nit: Instead of "Impl" let's call this something like
PrioritizingTaskQueueSelector to make its function clearer and to make it more
obvious why we need a different one for workers.

[alex clarke (OOO till 29th), 2015/03/27 10:55:29]

So PrioritizingTaskQueueSelector does sound like a better name. However I intend
to use PrioritizingTaskQueueSelector for workers too.

     : NON_EXPORTED_BASE(public TaskQueueSelector) {
  public:
   enum QueuePriority {
     // Queues with control priority will run before any other queue, and will
     // explicitly starve other queues. Typically this should only be used for
     // private queues which perform control operations.
     CONTROL_PRIORITY,
     // Queues with high priority will be selected preferentially over normal or
     // best effort queues. The selector will ensure that high priority queues
     // cannot completely starve normal priority queues.
     HIGH_PRIORITY,
     // Queues with normal priority are the default.
     NORMAL_PRIORITY,
     // Queues with best effort priority will only be run if all other queues are
     // empty. They can be starved by the other queues.
     BEST_EFFORT_PRIORITY,
     // Must be the last entry.
     QUEUE_PRIORITY_COUNT,
     FIRST_QUEUE_PRIORITY = CONTROL_PRIORITY,
   };
 
-  RendererTaskQueueSelector();
-  ~RendererTaskQueueSelector() override;
+  TaskQueueSelectorImpl();
+  ~TaskQueueSelectorImpl() override;
 
   // Set the priority of |queue_index| to |priority|.
   void SetQueuePriority(size_t queue_index, QueuePriority priority);
 
   // Enable the |queue_index| with a priority of |priority|. By default all
   // queues are enabled with normal priority.
   void EnableQueue(size_t queue_index, QueuePriority priority);
 
   // Disable the |queue_index|.
   void DisableQueue(size_t queue_index);
@@ skipping 33 matching lines @@
 
   // Number of high priority tasks which can be run before a normal priority
   // task should be selected to prevent starvation.
   // TODO(rmcilroy): Check if this is a good value.
   static const size_t kMaxStarvationTasks = 5;
 
   base::ThreadChecker main_thread_checker_;
   std::vector<const base::TaskQueue*> work_queues_;
   std::set<size_t> queue_priorities_[QUEUE_PRIORITY_COUNT];
   size_t starvation_count_;
-  DISALLOW_COPY_AND_ASSIGN(RendererTaskQueueSelector);
+  DISALLOW_COPY_AND_ASSIGN(TaskQueueSelectorImpl);
 };
 
 }  // namespace content
 
-#endif  // CONTENT_RENDERER_SCHEDULER_RENDERER_TASK_QUEUE_SELECTOR_H_
+#endif  // CONTENT_CHILD_SCHEDULER_TASK_QUEUE_SELECTOR_IMPL_H_