Update from https://crrev.com/320931

base/process/launch_posix.cc

 // 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.
 
 #include "base/process/launch.h"
 
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <sched.h>
@@ skipping 505 matching lines @@
 #if defined(OS_LINUX)
 #ifndef PR_SET_NO_NEW_PRIVS
 #define PR_SET_NO_NEW_PRIVS 38
 #endif
     if (!options.allow_new_privs) {
       if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) && errno != EINVAL) {
         // Only log if the error is not EINVAL (i.e. not supported).
         RAW_LOG(FATAL, "prctl(PR_SET_NO_NEW_PRIVS) failed");
       }
     }
+
+    if (options.kill_on_parent_death) {
+      if (prctl(PR_SET_PDEATHSIG, SIGKILL) != 0) {
+        RAW_LOG(ERROR, "prctl(PR_SET_PDEATHSIG) failed");
+        _exit(127);
+      }
+    }
 #endif
 
     if (current_directory != nullptr) {
       RAW_CHECK(chdir(current_directory) == 0);
     }
 
     if (options.pre_exec_delegate != nullptr) {
       options.pre_exec_delegate->RunAsyncSafe();
     }
 
@@ skipping 233 matching lines @@
   jmp_buf env;
   if (setjmp(env) == 0) {
     return CloneAndLongjmpInChild(flags, ptid, ctid, &env);
   }
 
   return 0;
 }
 #endif  // defined(OS_LINUX)
 
 }  // namespace base