Get rid of MessageLoop* caching in extensions code.

chrome/browser/automation/automation_provider.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/automation/automation_provider.h"
 
 #include <set>
 
 #include "app/l10n_util.h"
 #include "app/message_box_flags.h"
@@ skipping 2134 matching lines @@
 void AutomationProvider::InstallExtension(const FilePath& crx_path,
                                           IPC::Message* reply_message) {
   ExtensionsService* service = profile_->GetExtensionsService();
   if (service) {
     // The observer will delete itself when done.
     new ExtensionNotificationObserver(this,
                                       AutomationMsg_InstallExtension::ID,
                                       reply_message);
 
     const FilePath& install_dir = service->install_directory();
-    MessageLoop* io_loop = g_browser_process->file_thread()->message_loop();
-
     CrxInstaller::Start(crx_path,
                         install_dir,
                         Extension::INTERNAL,
                         "",  // no expected id
                         false,  // please do not delete crx file
                         true,  // privilege increase allowed
-                        io_loop,
                         service,
                         NULL);  // silent isntall, no UI
   } else {
     AutomationMsg_InstallExtension::WriteReplyParams(
         reply_message, AUTOMATION_MSG_EXTENSION_INSTALL_FAILED);
     Send(reply_message);
   }
 }
 
 void AutomationProvider::LoadExpandedExtension(
     const FilePath& extension_dir,
     IPC::Message* reply_message) {
   if (profile_->GetExtensionsService() && profile_->GetUserScriptMaster()) {
     // The observer will delete itself when done.
     new ExtensionNotificationObserver(this,
                                       AutomationMsg_LoadExpandedExtension::ID,
                                       reply_message);
 
     profile_->GetExtensionsService()->LoadExtension(extension_dir);
     profile_->GetUserScriptMaster()->AddWatchedPath(extension_dir);
   } else {
     AutomationMsg_LoadExpandedExtension::WriteReplyParams(
         reply_message, AUTOMATION_MSG_EXTENSION_INSTALL_FAILED);
     Send(reply_message);
   }
 }