Revert of scheduler: Add a base directory

components/scheduler/child/nestable_single_thread_task_runner.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_NESTABLE_SINGLE_THREAD_TASK_RUNNER_H_
+#define COMPONENTS_SCHEDULER_CHILD_NESTABLE_SINGLE_THREAD_TASK_RUNNER_H_
+
+#include "base/single_thread_task_runner.h"
+#include "base/message_loop/message_loop.h"
+#include "components/scheduler/scheduler_export.h"
+
+namespace scheduler {
+
+// A single thread task runner which exposes whether it is running nested.
+class SCHEDULER_EXPORT NestableSingleThreadTaskRunner
+    : public base::SingleThreadTaskRunner {
+ public:
+  NestableSingleThreadTaskRunner() {}
+
+  // Returns true if the task runner is nested (i.e., running a run loop within
+  // a nested task).
+  virtual bool IsNested() const = 0;
+
+ protected:
+  ~NestableSingleThreadTaskRunner() override {}
+
+  DISALLOW_COPY_AND_ASSIGN(NestableSingleThreadTaskRunner);
+};
+
+}  // namespace scheduler
+
+#endif  // COMPONENTS_SCHEDULER_CHILD_NESTABLE_SINGLE_THREAD_TASK_RUNNER_H_