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diff --git a/sandbox/linux/services/namespace_sandbox.h b/sandbox/linux/services/namespace_sandbox.h
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+++ b/sandbox/linux/services/namespace_sandbox.h
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+// Copyright 2015 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_NAMESPACE_SANDBOX_H_
+#define SANDBOX_LINUX_SERVICES_NAMESPACE_SANDBOX_H_
+
+#include <sys/types.h>
+
+#include <string>
+#include <vector>
+
+#include "base/command_line.h"
+#include "base/macros.h"
+#include "base/process/launch.h"
+#include "base/process/process.h"
+#include "sandbox/sandbox_export.h"
+
+namespace sandbox {
+
+// Helper class for starting a process inside a new user, PID, and network
+// namespace. Before using a namespace sandbox, check for namespaces support
+// using Credentials::CanCreateProcessInNewUserNS.
+//
+// A typical use for "A" launching a sandboxed process "B" would be:
+// 1. A sets up a command line and launch options for process B.
+// 2. A launches B with LaunchProcess.
+// 3. B should be prepared to assume the role of init(1). In particular, apart
+//    from SIGKILL and SIGSTOP, B cannot receive any signal for which it does
+//    not have an explicit signal handler registered.
+//    If B dies, all the processes in the namespace will die.
+//    B can fork() and the parent can assume the role of init(1), by using
+//    CreateInitProcessReaper().
+// 4. B chroots using Credentials::MoveToNewUserNS() and
+//    Credentials::DropFileSystemAccess()
+// 5. B drops capabilities gained by entering the new user namespace with
+//    Credentials::DropAllCapabilities().
+class SANDBOX_EXPORT NamespaceSandbox {
+ public:
+#if !defined(OS_NACL_NONSFI)
+  static const int kDefaultExitCode = 1;
+
+  // Launch a new process inside its own user/PID/network namespaces (depending
+  // on kernel support). Requires at a minimum that user namespaces are
+  // supported (use Credentials::CanCreateProcessInNewUserNS to check this).
+  //
+  // pre_exec_delegate and clone_flags fields of LaunchOptions should be nullptr
+  // and 0, respectively, since this function makes a copy of options and
+  // overrides them.
+  static base::Process LaunchProcess(const base::CommandLine& cmdline,
+                                     const base::LaunchOptions& options);
+  static base::Process LaunchProcess(const std::vector<std::string>& argv,
+                                     const base::LaunchOptions& options);
+
+  // Forks a process in its own PID namespace. The child process is the init
+  // process inside of the PID namespace, so if the child needs to fork further,
+  // it should call CreateInitProcessReaper, which turns the init process into a
+  // reaper process.
+  //
+  // Otherwise, the child should setup handlers for signals which should
+  // terminate the process using InstallDefaultTerminationSignalHandlers or
+  // InstallTerminationSignalHandler. This works around the fact that init
+  // processes ignore such signals unless they have an explicit handler set.
+  //
+  // This function requries CAP_SYS_ADMIN. If |drop_capabilities_in_child| is
+  // true, then capabilities are dropped in the child.
+  static pid_t ForkInNewPidNamespace(bool drop_capabilities_in_child);
+
+  // Installs a signal handler for:
+  //
+  // SIGHUP, SIGINT, SIGABRT, SIGQUIT, SIGPIPE, SIGTERM, SIGUSR1, SIGUSR2
+  //
+  // that exits with kDefaultExitCode. These are signals whose default action is
+  // to terminate the program (apart from SIGILL, SIGFPE, and SIGSEGV, which
+  // will still terminate the process if e.g. an illegal instruction is
+  // encountered, etc.).
+  //
+  // If any of these already had a signal handler installed, this function will
+  // not override them.
+  static void InstallDefaultTerminationSignalHandlers();
+
+  // Installs a signal handler for |sig| which exits with |exit_code|. If a
+  // signal handler was already present for |sig|, does nothing and returns
+  // false.
+  static bool InstallTerminationSignalHandler(int sig, int exit_code);
+#endif  // !defined(OS_NACL_NONSFI)
+
+  // Returns whether the namespace sandbox created a new user, PID, and network
+  // namespace. In particular, InNewUserNamespace should return true iff the
+  // process was started via this class.
+  static bool InNewUserNamespace();
+  static bool InNewPidNamespace();
+  static bool InNewNetNamespace();
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(NamespaceSandbox);
+};
+
+}  // namespace sandbox
+
+#endif  // SANDBOX_LINUX_SERVICES_NAMESPACE_SANDBOX_H_