android: Fix importing pexpect on Mac

build/android/adb_profile_chrome.py

 #!/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.
 
 import gzip
 import logging
 import optparse
 import os
-import pexpect
 import re
 import sys
 import time
 
 from pylib import android_commands
 from pylib import constants
+from pylib import pexpect
 
 
 def _GetSupportedBrowsers():
   # Add aliases for backwards compatibility.
   supported_browsers = {
     'stable': constants.PACKAGE_INFO['chrome_stable'],
     'beta': constants.PACKAGE_INFO['chrome_beta'],
     'dev': constants.PACKAGE_INFO['chrome_dev'],
     'build': constants.PACKAGE_INFO['chrome'],
   }
@@ skipping 175 matching lines @@
     _StopTracing(adb, package_info)
   elif options.download:
     _DownloadLatestTrace(adb, options.compress)
   elif options.time:
     _CaptureAndDownloadTimedTrace(adb, package_info, categories, options.time,
                                   options.continuous, options.compress)
 
 
 if __name__ == '__main__':
   sys.exit(main())