Linux Sandbox: Stop GPU watchdog in accountable way.

sandbox/linux/services/thread_helpers.h

+// Copyright 2014 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 SANDBOX_LINUX_SERVICES_THREAD_HELPERS_H_
+#define SANDBOX_LINUX_SERVICES_THREAD_HELPERS_H_
+
+#include "base/basictypes.h"
+
+namespace base { class Thread; }
+
+namespace sandbox {
+
+class ThreadHelpers {
+ public:
+  // Check whether the current process is single threaded. |proc_self_tasks|
+  // should be a file descriptor to /proc/self/task/ and remains owned by the
+  // caller.
+  static bool IsSingleThreaded(int proc_self_task);
+
+  // Stop |thread| and ensure that it does not have an entry in
+  // /proc/self/task/ from the point of view of the current thread. This is
+  // the way to stop threads before calling IsSingleThreaded().
+  static bool StopThreadAndWatchProcFS(int proc_self_tasks,
+                                       base::Thread* thread);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(ThreadHelpers);
+};
+
+}  // namespace content
+
+#endif  // SANDBOX_LINUX_SERVICES_THREAD_HELPERS_H_