Update from chromium 62675d9fb31fb8cedc40f68e78e8445a74f362e7

sandbox/linux/services/thread_helpers.h

Index: sandbox/linux/services/thread_helpers.h
diff --git a/sandbox/linux/services/thread_helpers.h b/sandbox/linux/services/thread_helpers.h
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+++ b/sandbox/linux/services/thread_helpers.h
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+// 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"
+#include "sandbox/sandbox_export.h"
+
+namespace base { class Thread; }
+
+namespace sandbox {
+
+class SANDBOX_EXPORT ThreadHelpers {
+ public:
+  // Check whether the current process is single threaded. |proc_self_tasks|
+  // can be a file descriptor to /proc/self/task/ and remains owned by the
+  // caller or -1.
+  // If |proc_self_tasks| is -1, this method will open /proc/self/task/ and
+  // crash if it cannot.
+  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 sandbox
+
+#endif  // SANDBOX_LINUX_SERVICES_THREAD_HELPERS_H_