Revert of Redirect the MessageLoop's task runner to the renderer scheduler

components/scheduler/child/scheduler_helper.h

 // Copyright 2015 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 COMPONENTS_SCHEDULER_CHILD_SCHEDULER_HELPER_H_
 #define COMPONENTS_SCHEDULER_CHILD_SCHEDULER_HELPER_H_
 
 #include "components/scheduler/child/prioritizing_task_queue_selector.h"
 #include "components/scheduler/child/task_queue_manager.h"
 #include "components/scheduler/scheduler_export.h"
 
 namespace base {
 class TickClock;
 }
 
 namespace scheduler {
 
-class SchedulerTaskRunnerDelegate;
+class NestableSingleThreadTaskRunner;
 
 // Common scheduler functionality for default tasks.
 class SCHEDULER_EXPORT SchedulerHelper {
  public:
   // NOTE |total_task_queue_count| must be >= TASK_QUEUE_COUNT.
   // Category strings must have application lifetime (statics or
   // literals). They may not include " chars.
-  SchedulerHelper(scoped_refptr<SchedulerTaskRunnerDelegate> main_task_runner,
-                  const char* tracing_category,
-                  const char* disabled_by_default_tracing_category,
-                  const char* disabled_by_default_verbose_tracing_category,
-                  size_t total_task_queue_count);
+  SchedulerHelper(
+      scoped_refptr<NestableSingleThreadTaskRunner> main_task_runner,
+      const char* tracing_category,
+      const char* disabled_by_default_tracing_category,
+      const char* disabled_by_default_verbose_tracing_category,
+      size_t total_task_queue_count);
   ~SchedulerHelper();
 
   // Returns the default task runner.
   scoped_refptr<base::SingleThreadTaskRunner> DefaultTaskRunner();
 
   // Returns the control task runner.  Tasks posted to this runner are executed
   // with the highest priority. Care must be taken to avoid starvation of other
   // task queues.
   scoped_refptr<base::SingleThreadTaskRunner> ControlTaskRunner();
 
@@ skipping 56 matching lines @@
 
   // Test helpers.
   void SetTimeSourceForTesting(scoped_ptr<base::TickClock> time_source);
   void SetWorkBatchSizeForTesting(size_t work_batch_size);
   TaskQueueManager* GetTaskQueueManagerForTesting();
 
  private:
   friend class SchedulerHelperTest;
 
   base::ThreadChecker thread_checker_;
-  scoped_refptr<SchedulerTaskRunnerDelegate> main_task_runner_;
   scoped_ptr<PrioritizingTaskQueueSelector> task_queue_selector_;
   scoped_ptr<TaskQueueManager> task_queue_manager_;
 
   uint64 quiescence_monitored_task_queue_mask_;
 
   scoped_refptr<base::SingleThreadTaskRunner> control_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> control_after_wakeup_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> default_task_runner_;
 
   scoped_ptr<base::TickClock> time_source_;
 
   const char* tracing_category_;
   const char* disabled_by_default_tracing_category_;
 
   DISALLOW_COPY_AND_ASSIGN(SchedulerHelper);
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_CHILD_SCHEDULER_HELPER_H_