# File lib/selenium/webdriver/common/driver_extensions/takes_screenshot.rb, line 29
        def screenshot_as(format)
          case format
          when :base64
            bridge.getScreenshot
          when :png
            bridge.getScreenshot.unpack("m")[0]
          else
            raise Error::UnsupportedOperationError, "unsupported format: #{format.inspect}"
          end
        end