Clean up header files.

sandbox/linux/services/credentials_unittest.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 "sandbox/linux/services/credentials.h"
 
 #include <errno.h>
 #include <fcntl.h>
+#include <limits.h>
 #include <pthread.h>
 #include <signal.h>
 #include <stdio.h>
 #include <sys/capability.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 
 #include <vector>
 
@@ skipping 241 matching lines @@
   action.sa_handler = &SignalHandler;
   PCHECK(sigaction(SIGUSR1, &action, nullptr) == 0);
 
   PCHECK(raise(SIGUSR1) == 0);
   CHECK_EQ(1, signal_handler_called);
 }
 
 }  // namespace.
 
 }  // namespace sandbox.