Revert 176015 due to compilation error

chrome/browser/extensions/api/storage/settings_storage_factory.h

-// 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.
-
-#ifndef CHROME_BROWSER_EXTENSIONS_API_STORAGE_SETTINGS_STORAGE_FACTORY_H_
-#define CHROME_BROWSER_EXTENSIONS_API_STORAGE_SETTINGS_STORAGE_FACTORY_H_
-
-#include <string>
-
-#include "base/file_path.h"
-#include "base/memory/ref_counted.h"
-
-class ValueStore;
-
-namespace extensions {
-
-// Factory for creating SettingStorage instances.
-//
-// Refcouted because it's just too messy to distribute these objects between
-// SettingsBackend instances any other way.
-class SettingsStorageFactory
-    : public base::RefCountedThreadSafe<SettingsStorageFactory> {
- public:
-  // Creates a new ValueStore area for an extension under |base_path|.
-  // Return NULL to indicate failure.  Must be called on the FILE thread.
-  virtual ValueStore* Create(const FilePath& base_path,
-                             const std::string& extension_id) = 0;
-
- protected:
-  friend class base::RefCountedThreadSafe<SettingsStorageFactory>;
-  virtual ~SettingsStorageFactory() {}
-};
-
-}  // namespace extensions
-
-#endif  // CHROME_BROWSER_EXTENSIONS_API_STORAGE_SETTINGS_STORAGE_FACTORY_H_