NaCl: Clean up file descriptor setup in nacl_helper on linux

chrome/common/nacl_helper_linux.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_COMMON_NACL_HELPER_LINUX_H_
 #define CHROME_COMMON_NACL_HELPER_LINUX_H_
 
 // A mini-zygote specifically for Native Client. This file defines
 // constants used to implement communication between the nacl_helper
 // process and the Chrome zygote.
 
 // Used by Helper to tell Zygote it has started successfully.
 #define kNaClHelperStartupAck "NACLHELPER_OK"
 // Used by Zygote to ask Helper to fork a new NaCl loader.
 #define kNaClForkRequest "NACLFORK"
 
 // The next set of constants define global Linux file descriptors.
 // For communications between NaCl loader and browser.

[jam, 2013/01/10 17:37:50]

nit: should this be removed now?

[Mark Seaborn, 2013/01/10 17:43:19]

No, this comment still applies.  kNaClSandboxDescriptor is used for
communicating with the browser process.

 // See also content/common/zygote_main_linux.cc and
 // http://code.google.com/p/chromium/wiki/LinuxZygote
-#define kNaClBrowserDescriptor 3
+
 // For communications between NaCl loader and zygote.
-// We put the kNaClZygoteDescriptor on 3 together with the
-// kNaClBrowserDescriptor. They are never used at the same
-// time, and this prevents /dev/urandom from using the fd.
 #define kNaClZygoteDescriptor 3
 // For communications between the NaCl loader process and
 // the SUID sandbox.
 #define kNaClSandboxDescriptor 5
-// NOTE: kNaClBrowserDescriptor and kNaClSandboxDescriptor must match
-// content/browser/zygote_main_linux.cc kBrowserDescriptor and
+// NOTE: kNaClSandboxDescriptor must match
+// content/browser/zygote_main_linux.cc
 // kMagicSandboxIPCDescriptor.
 
 // A fork request from the Zygote to the helper includes an array
 // of three file descriptors. These constants are used as indicies
 // into the array.
 // Used to pass in the descriptor for talking to the Browser
 #define kNaClBrowserFDIndex 0
 // The next two are used in the protocol for discovering the
 // child processes real PID from within the SUID sandbox. See
 // http://code.google.com/p/chromium/wiki/LinuxZygote
 #define kNaClDummyFDIndex 1
 #define kNaClParentFDIndex 2
 
 #endif  // CHROME_COMMON_NACL_HELPER_LINUX_H_