Add RetainedRef uses where needed.

chrome/browser/themes/theme_service.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/themes/theme_service.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 823 matching lines @@
   if (!service)
     return;
 
   // Write the packed file to disk.
   base::FilePath pack_path =
       extension->path().Append(ui::MaterialDesignController::IsModeMaterial()
                                    ? chrome::kThemePackMaterialDesignFilename
                                    : chrome::kThemePackFilename);
   service->GetFileTaskRunner()->PostTask(
       FROM_HERE,
-      base::Bind(&WritePackToDiskCallback, pack, pack_path));
+      base::Bind(&WritePackToDiskCallback, base::RetainedRef(pack), pack_path));
 
   // Save only the extension path. The packed file which matches the
   // MaterialDesignController::Mode will be loaded via LoadThemePrefs().
   SavePackName(extension->path());
   SwapThemeSupplier(pack);
 }
 
 #if defined(ENABLE_SUPERVISED_USERS)
 bool ThemeService::IsSupervisedUser() const {
   return profile_->IsSupervised();
 }
 
 void ThemeService::SetSupervisedUserTheme() {
   SetCustomDefaultTheme(new SupervisedUserTheme);
 }
 #endif