Implement SequenceChecker, which is a generalization of ThreadChecker

base/test/null_task_runner.cc

Index: base/test/null_task_runner.cc
diff --git a/base/test/null_task_runner.cc b/base/test/null_task_runner.cc
new file mode 100644
index 0000000000000000000000000000000000000000..bf43e6d0a3ba7db9490150f46ef8f28bf77aa8b9
--- /dev/null
+++ b/base/test/null_task_runner.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/test/null_task_runner.h"
+
+namespace base {
+
+NullTaskRunner::NullTaskRunner() {}
+
+NullTaskRunner::~NullTaskRunner() {}
+
+bool NullTaskRunner::PostDelayedTask(
+    const tracked_objects::Location& from_here,
+    const base::Closure& task,
+    base::TimeDelta delay) {
+  return false;
+}
+
+bool NullTaskRunner::PostNonNestableDelayedTask(
+    const tracked_objects::Location& from_here,
+    const base::Closure& task,
+    base::TimeDelta delay) {
+  return false;
+}
+
+bool NullTaskRunner::RunsTasksOnCurrentThread() const {
+  return true;
+}
+
+}  // namespace