docs: def grab_selenium_chromedriver(redownload=False):
      r"""
      Automatically download selenium chrome driver if needed
  
      CommandLine:
          python -m utool.util_grabdata --test-grab_selenium_chromedriver:1
  
      Example:
          >>> # DISABLE_DOCTEST
          >>> ut.grab_selenium_chromedriver()
          >>> import selenium.webdriver
          >>> driver = selenium.webdriver.Chrome()
          >>> driver.get('http://www.google.com')
          >>> search_field = driver.find_element_by_name('q')
          >>> search_field.send_keys('puppies')
          >>> search_field.send_keys(selenium.webdriver.common.keys.Keys.ENTER)
  
      Example1:
          >>> # DISABLE_DOCTEST
          >>> import selenium.webdriver
          >>> driver = selenium.webdriver.Firefox()
          >>> driver.get('http://www.google.com')
          >>> search_field = driver.find_element_by_name('q')
          >>> search_field.send_keys('puppies')
          >>> search_field.send_keys(selenium.webdriver.common.keys.Keys.ENTER)
      """
      import utool as ut
      import os
      import stat
      # TODO: use a better download dir (but it must be in the PATh or selenium freaks out)
      chromedriver_dpath = ut.ensuredir(ut.truepath('~/bin'))
      chromedriver_fpath = join(chromedriver_dpath, 'chromedriver')
      if not ut.checkpath(chromedriver_fpath) or redownload:
          assert chromedriver_dpath in os.environ['PATH'].split(os.pathsep)
          # TODO: make this work for windows as well
          if ut.LINUX and ut.util_cplat.is64bit_python():
              import requests
              rsp = requests.get('http://chromedriver.storage.googleapis.com/LATEST_RELEASE', timeout=TIMEOUT)
              assert rsp.status_code == 200
              url = 'http://chromedriver.storage.googleapis.com/' + rsp.text.strip() + '/chromedriver_linux64.zip'
              ut.grab_zipped_url(url, download_dir=chromedriver_dpath, redownload=True)
          else:
              raise AssertionError('unsupported chrome driver getter script')
          if not ut.WIN32:
              st = os.stat(chromedriver_fpath)
              os.chmod(chromedriver_fpath, st.st_mode | stat.S_IEXEC)
      ut.assert_exists(chromedriver_fpath)
      os.environ['webdriver.chrome.driver'] = chromedriver_fpath
      return chromedriver_fpath