Update from https://crrev.com/333737

base/process/kill_posix.cc

 // Copyright (c) 2013 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/kill.h"
 
 #include <signal.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
@@ skipping 32 matching lines @@
     *exit_code = status;
 
   if (WIFSIGNALED(status)) {
     switch (WTERMSIG(status)) {
       case SIGABRT:
       case SIGBUS:
       case SIGFPE:
       case SIGILL:
       case SIGSEGV:
         return TERMINATION_STATUS_PROCESS_CRASHED;
+      case SIGKILL:
+#if defined(OS_CHROMEOS)
+        // On ChromeOS, only way a process gets kill by SIGKILL
+        // is by oom-killer.
+        return TERMINATION_STATUS_PROCESS_WAS_KILLED_BY_OOM;
+#endif
       case SIGINT:
-      case SIGKILL:
       case SIGTERM:
         return TERMINATION_STATUS_PROCESS_WAS_KILLED;
       default:
         break;
     }
   }
 
   if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
     return TERMINATION_STATUS_ABNORMAL_TERMINATION;
 
@@ skipping 150 matching lines @@
     return;
 
   BackgroundReaper* reaper = new BackgroundReaper(pid, 0);
   PlatformThread::CreateNonJoinable(0, reaper);
 }
 
 #endif  // !defined(OS_MACOSX)
 #endif  // !defined(OS_NACL_NONSFI)
 
 }  // namespace base