Add regex escaping code to Mac sandbox implementation and re-enable the utility process on OS X.

chrome/browser/utility_process_host.cc

 // Copyright (c) 2009 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/utility_process_host.h"
 
 #include "app/app_switches.h"
 #include "app/l10n_util.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
@@ skipping 37 matching lines @@
 
   Send(new UtilityMsg_ParseUpdateManifest(xml));
   return true;
 }
 
 FilePath UtilityProcessHost::GetUtilityProcessCmd() {
   return GetChildPath();
 }
 
 bool UtilityProcessHost::StartProcess(const FilePath& exposed_dir) {
-#if defined(OS_POSIX)
+#if defined(OS_LINUX)
   // TODO(port): We should not reach here on Linux (crbug.com/22703).
-  // (crbug.com/23837) covers enabling this on Linux/OS X.
+  // (crbug.com/23837) covers enabling this on Linux.
   NOTREACHED();
   return false;
 #endif
 
   // Name must be set or metrics_service will crash in any test which
   // launches a UtilityProcessHost.
   set_name(L"utility process");
 
   if (!CreateChannel())
     return false;
@@ skipping 68 matching lines @@
     IPC_MESSAGE_HANDLER(UtilityHostMsg_UnpackWebResource_Succeeded,
                         Client::OnUnpackWebResourceSucceeded)
     IPC_MESSAGE_HANDLER(UtilityHostMsg_UnpackWebResource_Failed,
                         Client::OnUnpackWebResourceFailed)
     IPC_MESSAGE_HANDLER(UtilityHostMsg_ParseUpdateManifest_Succeeded,
                         Client::OnParseUpdateManifestSucceeded)
     IPC_MESSAGE_HANDLER(UtilityHostMsg_ParseUpdateManifest_Failed,
                         Client::OnParseUpdateManifestFailed)
   IPC_END_MESSAGE_MAP_EX()
 }