scheduler: Encapsulate TaskQueueManager inside SchedulerHelper

content/child/scheduler/scheduler_helper.h

Index: content/child/scheduler/scheduler_helper.h
diff --git a/content/child/scheduler/scheduler_helper.h b/content/child/scheduler/scheduler_helper.h
index 9834380c3279d3234420b7541e6581e16e3f04b8..acb60532261cfcd02067f946c1f1b0fcc2fe6631 100644
--- a/content/child/scheduler/scheduler_helper.h
+++ b/content/child/scheduler/scheduler_helper.h
@@ -158,7 +158,10 @@ class CONTENT_EXPORT SchedulerHelper {
   base::TimeTicks Now() const;
   IdlePeriodState SchedulerIdlePeriodState() const;
   PrioritizingTaskQueueSelector* SchedulerTaskQueueSelector() const;
-  TaskQueueManager* SchedulerTaskQueueManager() const;
+  scoped_refptr<base::SingleThreadTaskRunner> TaskRunnerForQueue(
+      size_t queue_index) const;
+  void SetQueueName(size_t queue_index, const char* name);
+  bool IsQueueEmpty(size_t queue_index) const;
 
   // Test helpers.
   void SetTimeSourceForTesting(scoped_refptr<cc::TestNowSource> time_source);