Back out r22981, it may have caused Windows test failures.

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 "base/command_line.h"
 #include "base/file_util.h"
 #include "base/message_loop.h"
 #include "base/path_service.h"
@@ skipping 34 matching lines @@
 
 bool UtilityProcessHost::StartWebResourceUnpacker(const std::string& data) {
   if (!StartProcess(FilePath()))
     return false;
 
   Send(new UtilityMsg_UnpackWebResource(data));
   return true;
 }
 
 std::wstring UtilityProcessHost::GetUtilityProcessCmd() {
-  return GetChildPath();
+  std::wstring exe_path = CommandLine::ForCurrentProcess()->GetSwitchValue(
+      switches::kBrowserSubprocessPath);
+  if (exe_path.empty()) {
+    PathService::Get(base::FILE_EXE, &exe_path);
+  }
+  return exe_path;
 }
 
 bool UtilityProcessHost::StartProcess(const FilePath& exposed_dir) {
   // 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 70 matching lines @@
     IPC_MESSAGE_HANDLER(UtilityHostMsg_UnpackExtension_Succeeded,
                         Client::OnUnpackExtensionSucceeded)
     IPC_MESSAGE_HANDLER(UtilityHostMsg_UnpackExtension_Failed,
                         Client::OnUnpackExtensionFailed)
     IPC_MESSAGE_HANDLER(UtilityHostMsg_UnpackWebResource_Succeeded,
                         Client::OnUnpackWebResourceSucceeded)
     IPC_MESSAGE_HANDLER(UtilityHostMsg_UnpackWebResource_Failed,
                         Client::OnUnpackWebResourceFailed)
   IPC_END_MESSAGE_MAP_EX()
 }