FilePath: remove some functions that aren't really used.

base/file_path.h

Index: base/file_path.h
diff --git a/base/file_path.h b/base/file_path.h
index bdcb03a35dfaa32524967cd962ad3177a0ab4ba2..f60a80cd370e8a904e5a28b734ba965c16a87a8b 100644
--- a/base/file_path.h
+++ b/base/file_path.h
@@ -312,12 +312,6 @@ class BASE_API FilePath {
   //   ever use the result of that again as a path.
   static FilePath FromWStringHack(const std::wstring& wstring);
 
-  // Static helper method to write a StringType to a pickle.
-  static void WriteStringTypeToPickle(Pickle* pickle,
-                                      const FilePath::StringType& path);
-  static bool ReadStringTypeFromPickle(Pickle* pickle, void** iter,
-                                       FilePath::StringType* path);
-
   void WriteToPickle(Pickle* pickle);
   bool ReadFromPickle(Pickle* pickle, void** iter);