Move some XDG code from chrome to base.

chrome/common/chrome_paths.h

 // Copyright (c) 2006-2008 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_COMMON_CHROME_PATHS_H__
 #define CHROME_COMMON_CHROME_PATHS_H__
 
 #include "build/build_config.h"
 
 // This file declares path keys for the chrome module.  These can be used with
 // the PathService to access various special directories and files.
 
 namespace chrome {
 
 enum {
   PATH_START = 1000,
 
   DIR_APP = PATH_START,  // directory where dlls and data reside
   DIR_LOGS,              // directory where logs should be written
   DIR_USER_DATA,         // directory where user data can be written
-  DIR_USER_CACHE,        // directory where user cache data resides
   DIR_CRASH_DUMPS,       // directory where crash dumps are written
   DIR_USER_DESKTOP,      // directory that correspond to the desktop
   DIR_INSPECTOR,         // directory where web inspector is located
   DIR_APP_DICTIONARIES,  // directory where the global dictionaries are
   DIR_USER_DOCUMENTS,    // directory for a user's "My Documents"
   DIR_DEFAULT_DOWNLOADS, // directory for a user's "My Documents/Downloads"
   FILE_RESOURCE_MODULE,  // full path and filename of the module that contains
                          // embedded resources (version, strings, images, etc.)
   FILE_LOCAL_STATE,      // path and filename to the file in which machine/
                          // installation-specific state is saved
@@ skipping 14 matching lines @@
 
   PATH_END
 };
 
 // Call once to register the provider for the path keys defined above.
 void RegisterPathProvider();
 
 }  // namespace chrome
 
 #endif  // CHROME_COMMON_CHROME_PATHS_H__