Check for empty paths in path_util

chrome/browser/extensions/path_util.h

 // Copyright 2014 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_BROWSER_EXTENSIONS_PATH_UTIL_H_
 #define CHROME_BROWSER_EXTENSIONS_PATH_UTIL_H_
 
 #include "base/files/file_path.h"
 
 namespace extensions {
 namespace path_util {
 
 // Prettifies |source_path|, by replacing the user's home directory with "~"
 // (if applicable).
 // For OS X, prettifies |source_path| by localizing every component of the
 // path. Additionally, if the path is inside the user's home directory, then
 // replace the home directory component with "~".
+//
+// This function is tested in
+// chrome/browser/extensions/extension_path_util_unittest.cc.
 base::FilePath PrettifyPath(const base::FilePath& source_path);
 
 }  // namespace path_util
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_PATH_UTIL_H_