Instructions:
  1) Apply selenium_shadow_dom.patch to selenium.

     $ cd <selenium_dir>
     $ git apply <path_to_templating/chromedriver>/selenium_shadow_dom.patch
     $ ./go //javascript/chrome-driver:atoms

  2) Copy the output to chromedriver.

    $ cp build/javascript/chrome-driver/atoms.* \
          <chromium_dir>/src/third_party/webdriver/

  3) Apply the chromedriver_shadow_dom.patch to chromedriver.

    $ cd <chromium_dir>
    $ git apply <README_dir>/chromedriver_shadow_dom.patch

  4) Build chromedriver.

    $ ninja -C out/Release chromedriver

  5) Copy the new version of chromedriver to this directory

    $ cp <chromium dir>/src/out/Release/chromedriver <path_to_templating/chromedriver>/
