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

chrome/browser/worker_host/worker_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/worker_host/worker_process_host.h"
 
 #include <set>
 
 #include "base/command_line.h"
 #include "base/debug_util.h"
@@ skipping 70 matching lines @@
         i->renderer_process_id, i->render_view_route_id));
   }
 
   ChildProcessSecurityPolicy::GetInstance()->Remove(GetProcessId());
 }
 
 bool WorkerProcessHost::Init() {
   if (!CreateChannel())
     return false;
 
-  std::wstring exe_path = GetChildPath();
-  if (exe_path.empty())
+  std::wstring exe_path;
+  if (!PathService::Get(base::FILE_EXE, &exe_path))
     return false;
 
   CommandLine cmd_line(exe_path);
   cmd_line.AppendSwitchWithValue(switches::kProcessType,
                                  switches::kWorkerProcess);
   cmd_line.AppendSwitchWithValue(switches::kProcessChannelID,
                                  ASCIIToWide(channel_id()));
 
   if (CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableNativeWebWorkers)) {
@@ skipping 198 matching lines @@
 }
 
 void WorkerProcessHost::OnCancelCreateDedicatedWorker(int route_id) {
   WorkerService::GetInstance()->CancelCreateDedicatedWorker(
       GetProcessId(), route_id);
 }
 
 void WorkerProcessHost::OnForwardToWorker(const IPC::Message& message) {
   WorkerService::GetInstance()->ForwardMessage(message, GetProcessId());
 }