[tools/perf] Remove default values of benchmark_dirs and top_level_dir in chromium_config module (R…

tools/perf/run_tests

 #!/usr/bin/env python
 # Copyright 2013 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.
 
 """This script runs unit tests of the code in the perf directory.
 
 This script DOES NOT run benchmarks. run_benchmark does that.
 """
 
 import os
 import subprocess
 import sys
 
 from chrome_telemetry_build import chromium_config
 from core import path_util
 
 path_util.AddTelemetryToPath()
 from telemetry.testing import unittest_runner
 
 
 def main():
-  project_config = chromium_config.ChromiumConfig()
+  project_config = chromium_config.ChromiumConfig(
+      top_level_dir=path_util.GetPerfDir())
   return unittest_runner.Run(project_config)
 
 if __name__ == '__main__':
   sys.exit(main())