Introduce a SchedulerHelper in content/child/scheduler

content/child/scheduler/task_queue_manager.h

Index: content/child/scheduler/task_queue_manager.h
diff --git a/content/renderer/scheduler/task_queue_manager.h b/content/child/scheduler/task_queue_manager.h
similarity index 96%
rename from content/renderer/scheduler/task_queue_manager.h
rename to content/child/scheduler/task_queue_manager.h
index ae38cc8be5db6596f959c7ac5d397160ae769f33..e8563ee6fd1bf369e9ba180383a388f91dd72eda 100644
--- a/content/renderer/scheduler/task_queue_manager.h
+++ b/content/child/scheduler/task_queue_manager.h
@@ -69,11 +69,13 @@ class CONTENT_EXPORT TaskQueueManager {
   // 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.
+  // It should outlive this class.  Category strings must have application
+  // lifetime (statics or literals). They may not include " chars.
   TaskQueueManager(
       size_t task_queue_count,
       scoped_refptr<NestableSingleThreadTaskRunner> main_task_runner,
-      TaskQueueSelector* selector);
+      TaskQueueSelector* selector,
+      const char* disabled_by_default_tracing_category);
   ~TaskQueueManager();
 
   // Returns the task runner which targets the queue selected by |queue_index|.
@@ -194,6 +196,8 @@ class CONTENT_EXPORT TaskQueueManager {
 
   ObserverList<base::MessageLoop::TaskObserver> task_observers_;
 
+  const char* disabled_by_default_tracing_category_;
+
   base::WeakPtrFactory<TaskQueueManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskQueueManager);