Make SequencedWorkerPool::IsRunningSequenceOnCurrentThread() private.

base/threading/sequenced_worker_pool.h

Index: base/threading/sequenced_worker_pool.h
diff --git a/base/threading/sequenced_worker_pool.h b/base/threading/sequenced_worker_pool.h
index 0e916c8782bbfe9e0230e2ec1a73d32f0a513680..67673a06341c0ed8d43a1087abbc7a9b1ad02a1e 100644
--- a/base/threading/sequenced_worker_pool.h
+++ b/base/threading/sequenced_worker_pool.h
@@ -323,10 +323,6 @@ class BASE_EXPORT SequencedWorkerPool : public TaskRunner {
                        TimeDelta delay) override;
   bool RunsTasksOnCurrentThread() const override;
 
-  // Returns true if the current thread is processing a task with the given
-  // sequence_token.
-  bool IsRunningSequenceOnCurrentThread(SequenceToken sequence_token) const;
-
   // Blocks until all pending tasks are complete. This should only be called in
   // unit tests when you want to validate something that should have happened.
   // This will not flush delayed tasks; delayed tasks get deleted.
@@ -370,9 +366,14 @@ class BASE_EXPORT SequencedWorkerPool : public TaskRunner {
   friend class RefCountedThreadSafe<SequencedWorkerPool>;
   friend class DeleteHelper<SequencedWorkerPool>;
 
+  class SequencedWorkerPoolSequencedTaskRunner;
   class Inner;
   class Worker;
 
+  // Returns true if the current thread is processing a task with the given
+  // sequence_token.
+  bool IsRunningSequenceOnCurrentThread(SequenceToken sequence_token) const;
+
   const scoped_refptr<SingleThreadTaskRunner> constructor_task_runner_;
 
   // Avoid pulling in too many headers by putting (almost) everything