Use base::GlobalDescriptors::kBaseDescriptor instead of magic number 3.

chrome/utility/importer/firefox_importer_unittest_utils_mac.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 "chrome/utility/importer/firefox_importer_unittest_utils.h"
 
 #include "base/base_switches.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/message_loop/message_loop.h"
+#include "base/posix/global_descriptors.h"
 #include "base/process/kill.h"
 #include "base/process/launch.h"
 #include "base/test/test_timeouts.h"
 #include "chrome/common/importer/firefox_importer_utils.h"
 #include "ipc/ipc_channel.h"
 #include "ipc/ipc_descriptors.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_message.h"
 #include "ipc/ipc_multiprocess_test.h"
 #include "ipc/ipc_switches.h"
@@ skipping 22 matching lines @@
   // why we need this.
   base::LaunchOptions options;
   options.environ["DYLD_FALLBACK_LIBRARY_PATH"] = nss_path.value();
 
   int ipcfd = channel->TakeClientFileDescriptor();
   if (ipcfd == -1)
     return false;
 
   file_util::ScopedFD client_file_descriptor_closer(&ipcfd);
   base::FileHandleMappingVector fds_to_map;
-  fds_to_map.push_back(std::pair<int,int>(ipcfd, kPrimaryIPCChannel + 3));
+  fds_to_map.push_back(std::pair<int,int>(ipcfd,
+      kPrimaryIPCChannel + base::GlobalDescriptors::kBaseDescriptor));
 
   bool debug_on_start = CommandLine::ForCurrentProcess()->HasSwitch(
                             switches::kDebugChildren);
   options.fds_to_remap = &fds_to_map;
   options.wait = debug_on_start;
   return base::LaunchProcess(cl.argv(), options, handle);
 }
 
 }  // namespace
 
@@ skipping 202 matching lines @@
 
   IPC::Channel channel(kTestChannelID, IPC::Channel::MODE_CLIENT, &listener);
   CHECK(channel.Connect());
   listener.SetSender(&channel);
 
   // run message loop
   base::MessageLoop::current()->Run();
 
   return 0;
 }