Update from https://crrev.com/327068

sandbox/linux/system_headers/arm_linux_syscalls.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.
 
 // Generated from the Linux kernel's calls.S.
 #ifndef SANDBOX_LINUX_SYSTEM_HEADERS_ARM_LINUX_SYSCALLS_H_
 #define SANDBOX_LINUX_SYSTEM_HEADERS_ARM_LINUX_SYSCALLS_H_
 
 #if !defined(__arm__) || !defined(__ARM_EABI__)
 #error "Including header on wrong architecture"
 #endif
 
-// __NR_SYSCALL_BASE, __ARM_NR_BASE are defined in <asm/unistd.h>.
-#include <asm/unistd.h>
+#if !defined(__NR_SYSCALL_BASE)
+// On ARM EABI arch, __NR_SYSCALL_BASE is 0.
+#define __NR_SYSCALL_BASE 0
+#endif
 
 // This syscall list has holes, because ARM EABI makes some syscalls obsolete.
 
 #if !defined(__NR_restart_syscall)
 #define __NR_restart_syscall (__NR_SYSCALL_BASE+0)
 #endif
 
 #if !defined(__NR_exit)
 #define __NR_exit (__NR_SYSCALL_BASE+1)
 #endif
@@ skipping 1348 matching lines @@
 
 #if !defined(__NR_getrandom)
 #define __NR_getrandom (__NR_SYSCALL_BASE+384)
 #endif
 
 #if !defined(__NR_memfd_create)
 #define __NR_memfd_create (__NR_SYSCALL_BASE+385)
 #endif
 
 // ARM private syscalls.
+#if !defined(__ARM_NR_BASE)
+#define __ARM_NR_BASE (__NR_SYSCALL_BASE + 0xF0000)
+#endif
+
 #if !defined(__ARM_NR_breakpoint)
 #define __ARM_NR_breakpoint (__ARM_NR_BASE+1)
 #endif
 
 #if !defined(__ARM_NR_cacheflush)
 #define __ARM_NR_cacheflush (__ARM_NR_BASE+2)
 #endif
 
 #if !defined(__ARM_NR_usr26)
 #define __ARM_NR_usr26 (__ARM_NR_BASE+3)
 #endif
 
 #if !defined(__ARM_NR_usr32)
 #define __ARM_NR_usr32 (__ARM_NR_BASE+4)
 #endif
 
 #if !defined(__ARM_NR_set_tls)
 #define __ARM_NR_set_tls (__ARM_NR_BASE+5)
 #endif
 
 // ARM kernel private syscall.
 #if !defined(__ARM_NR_cmpxchg)
 #define __ARM_NR_cmpxchg (__ARM_NR_BASE+0x00fff0)
 #endif
 
 #endif  // SANDBOX_LINUX_SYSTEM_HEADERS_ARM_LINUX_SYSCALLS_H_
-