[Linux] Use PR_SET_NO_NEW_PRIVS by default in base/process/launch.h.

base/process/launch.cc

 // Copyright (c) 2013 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/process/launch.h"
 
 namespace base {
 
 LaunchOptions::LaunchOptions()
     : wait(false),
 #if defined(OS_WIN)
       start_hidden(false),
       handles_to_inherit(NULL),
       inherit_handles(false),
       as_user(NULL),
       empty_desktop_name(false),
       job_handle(NULL),
       stdin_handle(NULL),
       stdout_handle(NULL),
       stderr_handle(NULL),
       force_breakaway_from_job_(false)
 #else
       fds_to_remap(NULL),
       maximize_rlimits(NULL),
       new_process_group(false)
 #if defined(OS_LINUX)
       , clone_flags(0)
+      , allow_new_privs(false)
 #endif  // OS_LINUX
 #if defined(OS_CHROMEOS)
       , ctrl_terminal_fd(-1)
 #endif  // OS_CHROMEOS
 #endif  // !defined(OS_WIN)
     {
 }
 
 LaunchOptions::~LaunchOptions() {
 }
 
+LaunchOptions LaunchOptionsForTest() {
+  LaunchOptions options;
+#if defined(OS_LINUX)
+  // To prevent accidental privilege sharing to an untrusted child, processes
+  // are started with PR_SET_NO_NEW_PRIVS. Do not set that here, since this
+  // new child will be used for testing only.
+  options.allow_new_privs = true;
+#endif
+  return options;
+}
+
 }  // namespace base