fix WebSocket handshake without SafeBrowsing

[xsmile]

With 570141 WebSocket handshakes are broken if safebrowsing is disabled, see #112.

This change fixes the issue.

[gcarq]

Good catch

[Eloston]

Nice find, and nice work! It just seemed too strange and unnecessary for SafeBrowsing to touch WebSockets, but I guess SafeBrowsing wouldn't be considered safe without checking everything that goes through the browser.

Out of curiosity, how did you find this change? Did you just search through the list of changes, or did something in the code hint towards it?

[xsmile]

@Eloston, Going through the changes in the safebrowsing patch one more time, I couldn't find anything useful and then had the assumption that Chromium might still use some parts of SafeBrowsing when handling WebSockets. Since the safe_browsing_service is no more, this obviously leads to problems.

I found the commit rather by accident while looking up the kNetworkService option.