FilePath: Remove most of ToWStringHack, adding a LossyDisplayName()

base/file_path.h

 // Copyright (c) 2010 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.
 
 // FilePath is a container for pathnames stored in a platform's native string
 // type, providing containers for manipulation in according with the
 // platform's conventions for pathnames.  It supports the following path
 // types:
 //
 //                   POSIX            Windows
@@ skipping 259 matching lines @@
   bool IsAbsolute() const;
 
   // Returns a copy of this FilePath that does not end with a trailing
   // separator.
   FilePath StripTrailingSeparators() const;
 
   // Returns true if this FilePath contains any attempt to reference a parent
   // directory (i.e. has a path component that is ".."
   bool ReferencesParent() const;
 
+  // Return a Unicode human-readable version of this path.
+  // Warning: you can *not*, in general, go from a display name back to a real
+  // path.  Only use this when displaying paths to users, not just when you
+  // want to stuff a string16 into some other API.
+  string16 LossyDisplayName() const;
+
   // Older Chromium code assumes that paths are always wstrings.
   // These functions convert wstrings to/from FilePaths, and are
   // useful to smooth porting that old code to the FilePath API.
   // They have "Hack" in their names so people feel bad about using them.
   // http://code.google.com/p/chromium/issues/detail?id=24672
   //
   // If you are trying to be a good citizen and remove these, ask yourself:
   // - Am I interacting with other Chrome code that deals with files?  Then
   //   try to convert the API into using FilePath.
   // - Am I interacting with OS-native calls?  Then use value() to get at an
   //   OS-native string format.
   // - Am I using well-known file names, like "config.ini"?  Then use the
   //   ASCII functions (we require paths to always be supersets of ASCII).
+  // - Am I displaying a string to the user in some UI?  Then use the
+  //   LossyDisplayName() function, but keep in mind that you can't
+  //   ever use the result of that again as a path.
   static FilePath FromWStringHack(const std::wstring& wstring);
   std::wstring ToWStringHack() const;
 
   // 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);
@@ skipping 79 matching lines @@
 namespace stdext {
 
 inline size_t hash_value(const FilePath& f) {
   return hash_value(f.value());
 }
 
 }  // namespace stdext
 #endif  // COMPILER
 
 #endif  // BASE_FILE_PATH_H_