Remove _unit_test_config hack, instead use FileSystem() in cpp.py & cpp_unittest.py

Tools/Scripts/webkitpy/common/system/filesystem.py

 # Copyright (C) 2010 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 188 matching lines @@
             f.write(contents)
 
     def open_text_file_for_reading(self, path):
         # Note: There appears to be an issue with the returned file objects
         # not being seekable. See http://stackoverflow.com/questions/1510188/can-seek-and-tell-work-with-utf-8-encoded-documents-in-python .
         return codecs.open(path, 'r', 'utf8')
 
     def open_text_file_for_writing(self, path):
         return codecs.open(path, 'w', 'utf8')
 
-    def read_text_file(self, path):
+    def read_text_file(self, path, errors='strict'):

[Dirk Pranke, 2013/10/22 19:17:03]

Are you sure we need this? I.e., does test-webkitpy include test cases that need
replaced content?

         """Return the contents of the file at the given path as a Unicode string.
 
         The file is read assuming it is a UTF-8 encoded file with no BOM."""
-        with codecs.open(path, 'r', 'utf8') as f:
+        with codecs.open(path, 'r', 'utf8', errors) as f:
             return f.read()
 
     def write_text_file(self, path, contents):
         """Write the contents to the file at the given location.
 
         The file is written encoded as UTF-8 with no BOM."""
         with codecs.open(path, 'w', 'utf8') as f:
             f.write(contents)
 
     def sha1(self, path):
@@ skipping 36 matching lines @@
     def copytree(self, source, destination):
         shutil.copytree(source, destination)
 
     def split(self, path):
         """Return (dirname, basename + '.' + ext)"""
         return os.path.split(path)
 
     def splitext(self, path):
         """Return (dirname + os.sep + basename, '.' + ext)"""
         return os.path.splitext(path)