renderers/gtk: Add a timeout for channel wainting for result.
renderers/gtk: Add a timeout for channel wainting for result.

While this is unlikely to ever get useful due to browser.drain() used
with the timeout of 5 seconds, this is a good precaution for long
waiting.

Should it be 10 seconds, though?

jmercouris/NeXT,jmercouris/NeXT