Make GlobalDescriptors::MaybeGet return -1 when the key is not found.

chrome/browser/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/browser/importer/firefox_importer_unittest_utils.h"
 
 #include "base/bind.h"
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
+#include "base/global_descriptors_posix.h"
 #include "base/message_loop.h"
 #include "base/test/test_timeouts.h"
 #include "chrome/browser/importer/firefox_importer_utils.h"
 #include "ipc/ipc_channel.h"
 #include "ipc/ipc_descriptors.h"
 #include "ipc/ipc_message.h"
 #include "ipc/ipc_switches.h"
+#include "ipc/ipc_tests.h"
 #include "testing/multiprocess_func_list.h"
 
 #define IPC_MESSAGE_IMPL
 #include "chrome/browser/importer/firefox_importer_unittest_messages_internal.h"
 
 namespace {
 
 // Name of IPC Channel to use for Server<-> Child Communications.
 const char kTestChannelID[] = "T1";
 
@@ skipping 227 matching lines @@
   virtual void OnChannelError() {
     MessageLoop::current()->Quit();
   }
 
  private:
   NSSDecryptor decryptor_;
   IPC::Message::Sender* sender_;
 };
 
 // Entry function in child process.
-MULTIPROCESS_TEST_MAIN(NSSDecrypterChildProcess) {
+MULTIPROCESS_TEST_MAIN(NSSDecrypterChildProcess, MultiProcessTestIPCSetUp) {
   MessageLoopForIO main_message_loop;
   FFDecryptorClientChannelListener listener;
 
   IPC::Channel channel(kTestChannelID, IPC::Channel::MODE_CLIENT, &listener);
   CHECK(channel.Connect());
   listener.SetSender(&channel);
 
   // run message loop
   MessageLoop::current()->Run();
 
   return 0;
 }