Reference CL for the new task scheduler.

base/task_scheduler/scheduler_lock.h

Index: base/task_scheduler/scheduler_lock.h
diff --git a/base/task_scheduler/scheduler_lock.h b/base/task_scheduler/scheduler_lock.h
new file mode 100644
index 0000000000000000000000000000000000000000..b8bc1b247098f3ac130609f4487904514496baab
--- /dev/null
+++ b/base/task_scheduler/scheduler_lock.h
@@ -0,0 +1,56 @@
+// Copyright 2016 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 BASE_TASK_SCHEDULER_SCHEDULER_LOCK_H
+#define BASE_TASK_SCHEDULER_SCHEDULER_LOCK_H
+
+#include <vector>
+
+#include "base/base_export.h"
+#include "base/macros.h"
+#include "base/synchronization/lock.h"
+
+namespace base {
+namespace internal {
+
+// A regular lock with simple deadlock correctness checking.
+// This lock is used throughout the scheduler, and when DCHECK_IS_ON(), tracks
+// all of the available locks to make sure that any locks are acquired in
+// an expected order.
+class BASE_EXPORT SchedulerLock {
+ public:
+  SchedulerLock();
+  explicit SchedulerLock(const SchedulerLock* predecessor);
+  ~SchedulerLock();
+
+  void Acquire();
+  void Release();
+
+  Lock* RawLockForConditionVariable();
+
+ private:
+  Lock lock_;
+
+  DISALLOW_COPY_AND_ASSIGN(SchedulerLock);
+};
+
+class AutoSchedulerLock {
+ public:
+  explicit AutoSchedulerLock(SchedulerLock& lock) : lock_(lock) {
+    lock_.Acquire();
+  }
+
+  ~AutoSchedulerLock() {
+    lock_.Release();
+  }
+
+ private:
+  SchedulerLock& lock_;
+  DISALLOW_COPY_AND_ASSIGN(AutoSchedulerLock);
+};
+
+}  // namespace internal
+}  // namespace base
+
+#endif  // BASE_TASK_SCHEDULER_SCHEDULER_LOCK_H