Introduce a SchedulerHelper in content/child/scheduler

content/child/scheduler/single_thread_idle_task_runner.h

Index: content/child/scheduler/single_thread_idle_task_runner.h
diff --git a/content/renderer/scheduler/single_thread_idle_task_runner.h b/content/child/scheduler/single_thread_idle_task_runner.h
similarity index 80%
rename from content/renderer/scheduler/single_thread_idle_task_runner.h
rename to content/child/scheduler/single_thread_idle_task_runner.h
index 1a4b0c1b6e2869df06049376941c09569ce57a24..089c0c8fc168bedd5551c1f8339050d17c278c06 100644
--- a/content/renderer/scheduler/single_thread_idle_task_runner.h
+++ b/content/child/scheduler/single_thread_idle_task_runner.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CONTENT_RENDERER_SCHEDULER_SINGLE_THREAD_IDLE_TASK_RUNNER_H_
-#define CONTENT_RENDERER_SCHEDULER_SINGLE_THREAD_IDLE_TASK_RUNNER_H_
+#ifndef CONTENT_CHILD_SCHEDULER_SINGLE_THREAD_IDLE_TASK_RUNNER_H_
+#define CONTENT_CHILD_SCHEDULER_SINGLE_THREAD_IDLE_TASK_RUNNER_H_
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ -22,10 +22,13 @@ class SingleThreadIdleTaskRunner
  public:
   typedef base::Callback<void(base::TimeTicks)> IdleTask;
 
+  // NOTE Category strings must have application lifetime (statics or
+  // literals). They may not include " chars.
   SingleThreadIdleTaskRunner(
       scoped_refptr<base::SingleThreadTaskRunner> idle_priority_task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> after_wakeup_task_runner,
-      base::Callback<void(base::TimeTicks*)> deadline_supplier);
+      base::Callback<void(base::TimeTicks*)> deadline_supplier,
+      const char* tracing_category);
 
   virtual void PostIdleTask(const tracked_objects::Location& from_here,
                             const IdleTask& idle_task);
@@ -51,9 +54,10 @@ class SingleThreadIdleTaskRunner
   scoped_refptr<base::SingleThreadTaskRunner> idle_priority_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> after_wakeup_task_runner_;
   base::Callback<void(base::TimeTicks*)> deadline_supplier_;
+  const char* tracing_category_;
   DISALLOW_COPY_AND_ASSIGN(SingleThreadIdleTaskRunner);
 };
 
 }  // namespace content
 
-#endif  // CONTENT_RENDERER_SCHEDULER_SINGLE_THREAD_IDLE_TASK_RUNNER_H_
+#endif  // CONTENT_CHILD_SCHEDULER_SINGLE_THREAD_IDLE_TASK_RUNNER_H_