Adds a flag to support "Virtual Time" to the blink scheduler

components/scheduler/base/task_queue_manager_delegate.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_BASE_TASK_QUEUE_MANAGER_DELEGATE_H_
+#define COMPONENTS_SCHEDULER_BASE_TASK_QUEUE_MANAGER_DELEGATE_H_
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/message_loop/message_loop.h"
+#include "base/time/tick_clock.h"
+#include "components/scheduler/scheduler_export.h"
+
+namespace scheduler {
+
+class SCHEDULER_EXPORT TaskQueueManagerDelegate
+    : public base::SingleThreadTaskRunner,
+      public base::TickClock {
+ public:
+  TaskQueueManagerDelegate() {}
+
+  // Returns true if the task runner is nested (i.e., running a run loop within
+  // a nested task).
+  virtual bool IsNested() const = 0;
+
+  // Used by the TaskQueueManager to tell us there is no more non-delayed work
+  // to do.
+  // TODO(alexclarke): Try and find a better interface that avoids the need for
+  // this.
+  virtual void OnNoMoreImmediateWork() = 0;
+
+ protected:
+  ~TaskQueueManagerDelegate() override {}
+
+  DISALLOW_COPY_AND_ASSIGN(TaskQueueManagerDelegate);
+};
+
+}  // namespace scheduler
+
+#endif  // COMPONENTS_SCHEDULER_BASE_TASK_QUEUE_MANAGER_DELEGATE_H_