Move some XDG code from chrome to base.

chrome/common/chrome_paths.cc

 // 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.
 
 #include "chrome/common/chrome_paths.h"
 
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/path_service.h"
@@ skipping 60 matching lines @@
 
   FilePath cur;
   switch (key) {
     case chrome::DIR_USER_DATA:
       if (!GetDefaultUserDataDirectory(&cur)) {
         NOTREACHED();
         return false;
       }
       create_dir = true;
       break;
-    case chrome::DIR_USER_CACHE:
-#if defined(OS_LINUX)
-      if (!GetUserCacheDirectory(&cur))
-        return false;
-      create_dir = true;
-#else
-      // No concept of a separate cache directory on non-Linux systems.
-      return false;
-#endif
-      break;
     case chrome::DIR_USER_DOCUMENTS:
       if (!GetUserDocumentsDirectory(&cur))
         return false;
       create_dir = true;
       break;
     case chrome::DIR_DEFAULT_DOWNLOADS:
       if (!GetUserDownloadsDirectory(&cur))
         return false;
       // Do not create the download directory here, we have done it twice now
       // and annoyed a lot of users.
@@ skipping 112 matching lines @@
   return true;
 }
 
 // This cannot be done as a static initializer sadly since Visual Studio will
 // eliminate this object file if there is no direct entry point into it.
 void RegisterPathProvider() {
   PathService::RegisterProvider(PathProvider, PATH_START, PATH_END);
 }
 
 }  // namespace chrome