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

content/browser/zygote_host/zygote_host_impl_linux.cc

 // 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 "content/browser/zygote_host/zygote_host_impl_linux.h"
 
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ skipping 148 matching lines @@
   int dummy_fd = -1;
   if (using_suid_sandbox_) {
     dummy_fd = socket(PF_UNIX, SOCK_DGRAM, 0);
     CHECK(dummy_fd >= 0);
     fds_to_map.push_back(std::make_pair(dummy_fd, kZygoteIdFd));
   }
 
   base::ProcessHandle process = -1;
   base::LaunchOptions options;
   options.fds_to_remap = &fds_to_map;
+  options.allow_new_privs = using_suid_sandbox_;  // Don't PR_SET_NO_NEW_PRIVS.
   base::LaunchProcess(cmd_line.argv(), options, &process);
   CHECK(process != -1) << "Failed to launch zygote process";
 
   if (using_suid_sandbox_) {
     // In the SUID sandbox, the real zygote is forked from the sandbox.
     // We need to look for it.
     // But first, wait for the zygote to tell us it's running.
     // The sending code is in content/browser/zygote_main_linux.cc.
     std::vector<int> fds_vec;
     const int kExpectedLength = sizeof(kZygoteHelloMessage);
@@ skipping 349 matching lines @@
   return RenderSandboxHostLinux::GetInstance()->pid();
 }
 
 int ZygoteHostImpl::GetSandboxStatus() const {
   if (have_read_sandbox_status_word_)
     return sandbox_status_;
   return 0;
 }
 
 }  // namespace content