Remove the open directory fd check.

sandbox/linux/services/credentials.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 "sandbox/linux/services/credentials.h"
 
 #include <errno.h>
 #include <signal.h>
 #include <stdio.h>
 #include <sys/capability.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/template_util.h"
 #include "base/third_party/valgrind/valgrind.h"
 #include "base/threading/thread.h"
-#include "sandbox/linux/services/proc_util.h"
 #include "sandbox/linux/services/syscall_wrappers.h"
 
 namespace {
 
 bool IsRunningOnValgrind() { return RUNNING_ON_VALGRIND; }
 
 struct CapFreeDeleter {
   inline void operator()(cap_t cap) const {
     int ret = cap_free(cap);
     CHECK_EQ(0, ret);
@@ skipping 206 matching lines @@
   DCHECK(GetRESIds(NULL, NULL));
   const char kGidMapFile[] = "/proc/self/gid_map";
   const char kUidMapFile[] = "/proc/self/uid_map";
   CHECK(WriteToIdMapFile(kGidMapFile, gid));
   CHECK(WriteToIdMapFile(kUidMapFile, uid));
   DCHECK(GetRESIds(NULL, NULL));
   return true;
 }
 
 bool Credentials::DropFileSystemAccess() {
-  // Chrooting to a safe empty dir will only be safe if no directory file
-  // descriptor is available to the process.
-  DCHECK(!ProcUtil::HasOpenDirectory(-1));
   return ChrootToSafeEmptyDir();
 }
 
 }  // namespace sandbox.