Fix relative file: paths in OWNERS with roots other than '/'

tests/owners_unittest.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """Unit tests for owners.py."""
 
 import os
 import sys
 import unittest
@@ skipping 210 matching lines @@
     self.assert_files_not_covered_by(['content/qux/bar.cc'], [peter], [])
     self.assert_files_not_covered_by(['content/qux/baz.cc'],
                                      [tom], ['content/qux/baz.cc'])
 
   def test_file_include_relative_path(self):
     self.assert_files_not_covered_by(['content/garply/foo.cc'], [peter], [])
     self.assert_files_not_covered_by(['content/garply/bar.cc'], [darin], [])
     self.assert_files_not_covered_by(['content/garply/baz.cc'],
                                      [tom], ['content/garply/baz.cc'])
 
+  def test_file_include_relative_path_non_empty_root(self):
+    old_root = self.root
+    self.root = '/content'
+    self.assert_files_not_covered_by(['garply/foo.cc'], [peter], [])
+    self.assert_files_not_covered_by(['garply/bar.cc'], [darin], [])
+    self.assert_files_not_covered_by(['garply/baz.cc'],
+                                     [tom], ['garply/baz.cc'])
+    self.root = old_root
+
   def test_file_include_per_file_absolute_path(self):
     self.files['/content/qux/OWNERS'] = owners_file(peter,
         lines=['per-file foo.*=file://content/baz/OWNERS'])
 
     self.assert_files_not_covered_by(['content/qux/foo.cc'], [brett], [])
     self.assert_files_not_covered_by(['content/qux/baz.cc'],
                                      [brett], ['content/qux/baz.cc'])
 
   def test_file_include_per_file_relative_path(self):
     self.files['/content/garply/OWNERS'] = owners_file(brett,
@@ skipping 235 matching lines @@
                       ('chrome/browser', 2)],
                 ken: [('chrome/gpu', 1)],
                 peter: [('chrome/renderer', 1)],
                 brett: [('chrome/browser', 1)]},
                ['chrome/gpu', 'chrome/renderer',
                 'chrome/browser'],
                ben)
 
 if __name__ == '__main__':
   unittest.main()