Update from https://crrev.com/305340

sandbox/linux/services/syscall_wrappers.cc

+// Copyright 2014 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 "sandbox/linux/services/syscall_wrappers.h"
+
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "base/logging.h"
+#include "build/build_config.h"
+#include "sandbox/linux/services/linux_syscalls.h"
+
+namespace sandbox {
+
+pid_t sys_getpid(void) {
+  return syscall(__NR_getpid);
+}
+
+pid_t sys_gettid(void) {
+  return syscall(__NR_gettid);
+}
+
+long sys_clone(unsigned long flags) {
+  return sys_clone(flags, nullptr, nullptr, nullptr, nullptr);
+}
+
+long sys_clone(unsigned long flags,
+               void* child_stack,
+               pid_t* ptid,
+               pid_t* ctid,
+               decltype(nullptr) tls) {
+  const bool clone_tls_used = flags & CLONE_SETTLS;
+  const bool invalid_ctid =
+      (flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) && !ctid;
+  const bool invalid_ptid = (flags & CLONE_PARENT_SETTID) && !ptid;
+  const bool invalid_stack = (flags & CLONE_VM) && !child_stack;
+
+  if (clone_tls_used || invalid_ctid || invalid_ptid || invalid_stack) {
+    RAW_LOG(FATAL, "Invalid usage of sys_clone");
+  }
+
+// See kernel/fork.c in Linux. There is different ordering of sys_clone
+// parameters depending on CONFIG_CLONE_BACKWARDS* configuration options.
+#if defined(ARCH_CPU_X86_64)
+  return syscall(__NR_clone, flags, child_stack, ptid, ctid, tls);
+#elif defined(ARCH_CPU_X86) || defined(ARCH_CPU_ARM_FAMILY) || \
+    defined(ARCH_CPU_MIPS_FAMILY) || defined(ARCH_CPU_MIPS64_FAMILY)
+  // CONFIG_CLONE_BACKWARDS defined.
+  return syscall(__NR_clone, flags, child_stack, ptid, tls, ctid);
+#endif
+}
+
+void sys_exit_group(int status) {
+  syscall(__NR_exit_group, status);
+}
+
+}  // namespace sandbox