Implement SequenceChecker, which is a generalization of ThreadChecker

base/sequence_checker_impl.cc

Index: base/sequence_checker_impl.cc
diff --git a/base/sequence_checker_impl.cc b/base/sequence_checker_impl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..24d9ed99a147c7c5a8d2db69557b3f891851cfa4
--- /dev/null
+++ b/base/sequence_checker_impl.cc
@@ -0,0 +1,31 @@
+// Copyright (c) 2012 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.
+
+#include "base/sequence_checker_impl.h"
+
+#include "base/sequenced_task_runner.h"
+
+namespace base {
+
+SequenceCheckerImpl::SequenceCheckerImpl(
+    const scoped_refptr<SequencedTaskRunner>& sequenced_task_runner)
+    : sequenced_task_runner_(sequenced_task_runner) {}
+
+SequenceCheckerImpl::~SequenceCheckerImpl() {}
+
+bool SequenceCheckerImpl::CalledOnValidSequence() const {
+  AutoLock auto_lock(lock_);
+  return sequenced_task_runner_.get() ?
+      sequenced_task_runner_->RunsTasksOnCurrentThread() :
+      thread_checker_.CalledOnValidThread();
+}
+
+void SequenceCheckerImpl::ChangeSequence(
+    const scoped_refptr<SequencedTaskRunner>& sequenced_task_runner) {
+  AutoLock auto_lock(lock_);
+  sequenced_task_runner_ = sequenced_task_runner;
+  thread_checker_.DetachFromThread();
+}
+
+}  // namespace base