Update from https://crrev.com/305340

sandbox/linux/services/syscall_wrappers_unittest.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 <sys/wait.h>
+#include <unistd.h>
+
+#include "base/logging.h"
+#include "base/posix/eintr_wrapper.h"
+#include "build/build_config.h"
+#include "sandbox/linux/tests/test_utils.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace sandbox {
+
+namespace {
+
+TEST(SyscallWrappers, BasicSyscalls) {
+  EXPECT_EQ(getpid(), sys_getpid());
+}
+
+TEST(SyscallWrappers, CloneBasic) {
+  pid_t child = sys_clone(SIGCHLD);
+  TestUtils::HandlePostForkReturn(child);
+  EXPECT_LT(0, child);
+}
+
+TEST(SyscallWrappers, CloneParentSettid) {
+  pid_t ptid = 0;
+  pid_t child = sys_clone(CLONE_PARENT_SETTID | SIGCHLD, nullptr, &ptid,
+                          nullptr, nullptr);
+  TestUtils::HandlePostForkReturn(child);
+  EXPECT_LT(0, child);
+  EXPECT_EQ(child, ptid);
+}
+
+TEST(SyscallWrappers, CloneChildSettid) {
+  pid_t ctid = 0;
+  pid_t pid =
+      sys_clone(CLONE_CHILD_SETTID | SIGCHLD, nullptr, nullptr, &ctid, nullptr);
+
+  const int kSuccessExit = 0;
+  if (0 == pid) {
+    // In child.
+    if (sys_getpid() == ctid)
+      _exit(kSuccessExit);
+    _exit(1);
+  }
+
+  ASSERT_NE(-1, pid);
+  int status = 0;
+  ASSERT_EQ(pid, HANDLE_EINTR(waitpid(pid, &status, 0)));
+  ASSERT_TRUE(WIFEXITED(status));
+  EXPECT_EQ(kSuccessExit, WEXITSTATUS(status));
+}
+
+}  // namespace
+
+}  // namespace sandbox