ChromeDriver

Chrome support is through the platform specific ChromeDriver binary, which you download and put on your path.

b = Watir::Browser.new :chrome

Chrome Profiles

profile = Selenium::WebDriver::Chrome::Profile.new
profile['download.prompt_for_download'] = false
profile['download.default_directory'] = "/path/to/dir"

b = Watir::Browser.new :chrome, :profile => profile

See the full list of profile options here.

Chrome Switches

b = Watir::Browser.new :chrome, :switches => %w[--ignore-certificate-errors --disable-popup-blocking --disable-translate]

See the full list of switches here.

Using a proxy with Chrome

b = Watir::Browser.new :chrome, :switches => %w[--proxy-server=myproxy.com:8080]