webkitpy: Memoize chromium_base() and depot_tools_base().

third_party/WebKit/Tools/Scripts/webkitpy/common/webkit_finder.py

 # Copyright (c) 2012 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 62 matching lines @@
     return os.path.join(get_scripts_dir(), 'webkitpy', 'thirdparty')
 
 
 class WebKitFinder(object):
 
     def __init__(self, filesystem):
         self._filesystem = filesystem
         self._dirsep = filesystem.sep
         self._sys_path = sys.path
         self._env_path = os.environ['PATH'].split(os.pathsep)
-        self._chromium_base = None
-        self._depot_tools = None
 
     @memoized
     def _webkit_base(self):
         """Returns the absolute path to the top of the WebKit tree.
 
         Raises an AssertionError if the top dir can't be determined.
         """
         # TODO(qyearsley): This code somewhat duplicates the code in
         # git.find_checkout_root().
         module_path = self._filesystem.abspath(self._filesystem.path_to_module(self.__module__))
         tools_index = module_path.rfind('Tools')
         assert tools_index != -1, 'could not find location of this checkout from %s' % module_path
         return self._filesystem.normpath(module_path[0:tools_index - 1])
 
+    @memoized
     def chromium_base(self):
-        if not self._chromium_base:
-            self._chromium_base = self._filesystem.dirname(self._filesystem.dirname(self._webkit_base()))
-        return self._chromium_base
+        return self._filesystem.dirname(self._filesystem.dirname(self._webkit_base()))
 
     # Do not expose this function in order to make the code robust against
     # directory structure changes.
     def _path_from_webkit_base(self, *comps):
         return self._filesystem.join(self._webkit_base(), *comps)
 
     def path_from_chromium_base(self, *comps):
         return self._filesystem.join(self.chromium_base(), *comps)
 
     def path_from_blink_source(self, *comps):
@@ skipping 26 matching lines @@
         Returns:
             The normalized layout test name, which is just the relative path from
             the LayoutTests directory, using forward slash as the path separator.
             Returns None if the given file is not in the LayoutTests directory.
         """
         layout_tests_rel_path = self._filesystem.relpath(self.layout_tests_dir(), self.chromium_base())
         if not file_path.startswith(layout_tests_rel_path):
             return None
         return file_path[len(layout_tests_rel_path) + 1:]
 
+    @memoized
     def depot_tools_base(self):
-        if not self._depot_tools:
-            # This basically duplicates src/build/find_depot_tools.py without the side effects
-            # (adding the directory to sys.path and importing breakpad).
-            self._depot_tools = (self._check_paths_for_depot_tools(self._sys_path) or
-                                 self._check_paths_for_depot_tools(self._env_path) or
-                                 self._check_upward_for_depot_tools())
-        return self._depot_tools
+        # This basically duplicates src/build/find_depot_tools.py without the side effects
+        # (adding the directory to sys.path and importing breakpad).
+        return (self._check_paths_for_depot_tools(self._sys_path) or
+                self._check_paths_for_depot_tools(self._env_path) or
+                self._check_upward_for_depot_tools())
 
     def _check_paths_for_depot_tools(self, paths):
         for path in paths:
             if path.rstrip(self._dirsep).endswith('depot_tools'):
                 return path
         return None
 
     def _check_upward_for_depot_tools(self):
         fs = self._filesystem
         prev_dir = ''
         current_dir = fs.dirname(self._webkit_base())
         while current_dir != prev_dir:
             if fs.exists(fs.join(current_dir, 'depot_tools', 'pylint.py')):
                 return fs.join(current_dir, 'depot_tools')
             prev_dir = current_dir
             current_dir = fs.dirname(current_dir)
 
     def path_from_depot_tools_base(self, *comps):
         return self._filesystem.join(self.depot_tools_base(), *comps)