Update from https://crrev.com/305340

sandbox/linux/tests/test_utils.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/tests/test_utils.h"
 
 #include <errno.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/wait.h>
@@ skipping 10 matching lines @@
   int ret = HANDLE_EINTR(
       waitid(P_ALL, 0, &process_info, WEXITED | WNOHANG | WNOWAIT));
   if (-1 == ret) {
     PCHECK(ECHILD == errno);
     return false;
   } else {
     return true;
   }
 }
 
+void TestUtils::HandlePostForkReturn(pid_t pid) {
+  const int kChildExitCode = 1;
+  if (pid > 0) {
+    int status = 0;
+    PCHECK(pid == HANDLE_EINTR(waitpid(pid, &status, 0)));
+    CHECK(WIFEXITED(status));
+    CHECK_EQ(kChildExitCode, WEXITSTATUS(status));
+  } else if (pid == 0) {
+    _exit(kChildExitCode);
+  }
+}
+
 }  // namespace sandbox