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

tools/perf/chrome_telemetry_build/chromium_config.py

 # Copyright 2015 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.
 
-import logging
 import os
-import sys
 
-
-def GetChromiumSrcDir():
-  return os.path.abspath(
-      os.path.join(os.path.abspath(__file__), '..', '..', '..', '..'))
-
-
-def GetTelemetryDir():
-  return os.path.join(GetChromiumSrcDir(), 'third_party', 'catapult',
-                      'telemetry')
+from core import path_util
 
 
 CLIENT_CONFIG_PATH = os.path.join(
     os.path.dirname(os.path.abspath(__file__)), 'binary_dependencies.json')
 
-sys.path.insert(1, os.path.join(GetTelemetryDir()))
+path_util.AddTelemetryToPath()
 
 from telemetry import project_config
 
 
 class ChromiumConfig(project_config.ProjectConfig):
 
   def __init__(self, top_level_dir=None, benchmark_dirs=None,
-               client_configs=None,
-               default_chrome_root=GetChromiumSrcDir()):
+               client_configs=None, default_chrome_root=None):
     if client_configs is None:
       client_configs = [CLIENT_CONFIG_PATH]
-
-    perf_dir = os.path.join(GetChromiumSrcDir(), 'tools', 'perf')
-    if not benchmark_dirs:
-      benchmark_dirs = [os.path.join(perf_dir, 'benchmarks')]
-      logging.info('No benchmark directories specified. Defaulting to %s',
-                   benchmark_dirs)
-    if not top_level_dir:
-      top_level_dir = perf_dir
-      logging.info('No top level directory specified. Defaulting to %s',
-                   top_level_dir)
+    if default_chrome_root is None:
+      default_chrome_root = path_util.GetChromiumSrcDir()
 
     super(ChromiumConfig, self).__init__(
         top_level_dir=top_level_dir, benchmark_dirs=benchmark_dirs,
         client_configs=client_configs, default_chrome_root=default_chrome_root)