Remove some deprecated file_util wstring functions.

chrome/installer/util/delete_tree_work_item.h

Index: chrome/installer/util/delete_tree_work_item.h
===================================================================
--- chrome/installer/util/delete_tree_work_item.h	(revision 29006)
+++ chrome/installer/util/delete_tree_work_item.h	(working copy)
@@ -7,6 +7,8 @@
 
 #include <string>
 #include <windows.h>
+
+#include "base/file_path.h"
 #include "chrome/installer/util/work_item.h"
 
 // A WorkItem subclass that recursively deletes a file system hierarchy at the
@@ -26,25 +28,25 @@
   friend class WorkItem;
 
   // Get a backup path that can keep root_path_ or key_path_
-  bool GetBackupPath(const std::wstring& for_path, std::wstring* backup_path);
+  bool GetBackupPath(const FilePath& for_path, FilePath* backup_path);
 
   DeleteTreeWorkItem(const std::wstring& root_path,
                      const std::wstring& key_path);
 
   // Root path to delete.
-  std::wstring root_path_;
+  FilePath root_path_;
 
   // Path to the key file. If the key file is specified, deletion will be
   // performed only if the key file is not in use.
-  std::wstring key_path_;
+  FilePath key_path_;
 
   // The full path in temporary directory that the original root_path_ has
   // been moved to.
-  std::wstring backup_path_;
+  FilePath backup_path_;
 
   // The full path in temporary directory that the original key_path_ has
   // been moved to.
-  std::wstring key_backup_path_;
+  FilePath key_backup_path_;
 };
 
 #endif  // CHROME_INSTALLER_UTIL_DELETE_TREE_WORK_ITEM_H_