wstring: use a few more FilePaths to remove Hack functions

chrome/installer/util/work_item.h

 // Copyright (c) 2011 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.
 //
 // Base class for managing an action of a sequence of actions to be carried
 // out during install/update/uninstall. Supports rollback of actions if this
 // process fails.
 
 #ifndef CHROME_INSTALLER_UTIL_WORK_ITEM_H_
 #define CHROME_INSTALLER_UTIL_WORK_ITEM_H_
@@ skipping 41 matching lines @@
 
   virtual ~WorkItem();
 
   // Create a CopyTreeWorkItem that recursively copies a file system hierarchy
   // from source path to destination path.
   // * If overwrite_option is ALWAYS, the created CopyTreeWorkItem always
   //   overwrites files.
   // * If overwrite_option is NEW_NAME_IF_IN_USE, file is copied with an
   //   alternate name specified by alternative_path.
   static CopyTreeWorkItem* CreateCopyTreeWorkItem(
-      const std::wstring& source_path,
-      const std::wstring& dest_path,
-      const std::wstring& temp_dir,
+      const FilePath& source_path,
+      const FilePath& dest_path,
+      const FilePath& temp_dir,
       CopyOverWriteOption overwrite_option,
-      const std::wstring& alternative_path = L"");
+      const FilePath& alternative_path);
 
   // Create a CreateDirWorkItem that creates a directory at the given path.
   static CreateDirWorkItem* CreateCreateDirWorkItem(const FilePath& path);
 
   // Create a CreateRegKeyWorkItem that creates a registry key at the given
   // path.
   static CreateRegKeyWorkItem* CreateCreateRegKeyWorkItem(
       HKEY predefined_root, const std::wstring& path);
 
   // Create a DeleteRegKeyWorkItem that deletes a registry key at the given
@@ skipping 96 matching lines @@
   WorkItem();
 
   // Specifies whether this work item my fail to complete and yet still
   // return true from Do().
   bool ignore_failure_;
 
   std::string log_message_;
 };
 
 #endif  // CHROME_INSTALLER_UTIL_WORK_ITEM_H_