chrome_paths: refactor and sanitize cache directory handling

base/base_paths_linux.cc

 // 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.
 
 #include "base/base_paths.h"
 
 #include <unistd.h>
 #if defined(OS_FREEBSD)
 #include <sys/param.h>
 #include <sys/sysctl.h>
@@ skipping 87 matching lines @@
       // drive) try assuming the current directory is the source root.
       if (file_util::GetCurrentDirectory(&path) &&
           file_util::PathExists(path.Append(kThisSourceFile))) {
         *result = path;
         return true;
       }
       LOG(ERROR) << "Couldn't find your source root.  "
                  << "Try running from your chromium/src directory.";
       return false;
     }
-    case base::DIR_USER_CACHE:
+    case base::DIR_CACHE:
       scoped_ptr<base::Environment> env(base::Environment::Create());
       FilePath cache_dir(base::nix::GetXDGDirectory(env.get(), "XDG_CACHE_HOME",
                                                     ".cache"));
       *result = cache_dir;
       return true;
   }
   return false;
 }
 
 }  // namespace base