Will now DCHECK that test writers start the embedded server before using it.

Will now DCHECK that test writers start the embedded server before using it.

One developer on my team was writing a browser test, but the test would just
hang. Turns out he forgot to start the embedded test server.

I think we can make the failure a lot clearer by adding a DCHECK which will
clearly point out the problem. I know that GetURL doesn't mean the test makes
a request to the server as such, but the returned URL will almost always be
fed into a NavigateToUrl request, so checking for this here will probably
be helpful in almost all cases.

R=phajdan.jr@chromium.org
BUG=301625
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=226441

[Paweł Hajdan Jr., 2013-09-30 18:12:24]

LGTM

[phoglund_chromium, 2013-10-01 07:38:30]

sky: I found two tests which did not init the embedded test server, but somehow
seemed to work anyway (this will typically not be the case). Please review the
test changes; see CL description for more info.

[sky, 2013-10-01 17:36:06]

LGTM

[commit-bot: I haz the power, 2013-10-02 07:50:39]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/phoglund@chromium.org/25238003/21001

[commit-bot: I haz the power, 2013-10-02 10:10:07]

Change committed as 226441