Refactor the setuid sandbox client code to its own class.

base/linux_util.h

 // 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.
 
 #ifndef BASE_LINUX_UTIL_H_
 #define BASE_LINUX_UTIL_H_
 
 #include <stdint.h>
 #include <sys/types.h>
 
 #include <string>
 
 #include "base/base_export.h"
 
 namespace base {
 
 BASE_EXPORT extern const char kFindInodeSwitch[];
 
-// This should be kept in sync with sandbox/linux/suid/sandbox.c
-BASE_EXPORT extern const long kSUIDSandboxApiNumber;
-BASE_EXPORT extern const char kSandboxEnvironmentApiRequest[];
-BASE_EXPORT extern const char kSandboxEnvironmentApiProvides[];
-
 // This is declared here so the crash reporter can access the memory directly
 // in compromised context without going through the standard library.
 BASE_EXPORT extern char g_linux_distro[];
 
 // Get the Linux Distro if we can, or return "Unknown".
 BASE_EXPORT std::string GetLinuxDistro();
 
 // Set the Linux Distro string.
 BASE_EXPORT void SetLinuxDistro(const std::string& distro);
 
 // Return the inode number for the UNIX domain socket |fd|.
 BASE_EXPORT bool FileDescriptorGetInode(ino_t* inode_out, int fd);
 
 // Find the process which holds the given socket, named by inode number. If
 // multiple processes hold the socket, this function returns false.
 BASE_EXPORT bool FindProcessHoldingSocket(pid_t* pid_out, ino_t socket_inode);
 
 // For a given process |pid|, look through all its threads and find the first
 // thread with /proc/[pid]/task/[thread_id]/syscall whose first N bytes matches
 // |expected_data|, where N is the length of |expected_data|.
 // Returns the thread id or -1 on error.  If |syscall_supported| is
 // set to false the kernel does not support syscall in procfs.
 BASE_EXPORT pid_t FindThreadIDWithSyscall(pid_t pid,
                                           const std::string& expected_data,
                                           bool* syscall_supported);
 
 }  // namespace base
 
 #endif  // BASE_LINUX_UTIL_H_