Turn off the network proxy for mac and win in DRT

Turn off the network proxy for mac and win in DRT

The original test_shell code was written to use the system proxy
autoconfig. On windows, at least, this was known to be flaky at best.
However, this still made sense because we needed to be able to use
test_shell to view arbitrary pages on the web, and we didn't have an
alternative.

However, we don't really use test_shell anymore, and the same code
is used by DumpRenderTree, which only views pages on the local machine
and has no need for the proxy at all. This patch changes the net config
to never use a proxy on any platform.

R=tony@chromium.org, eroman@chromium.org
BUG=170429
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=181358

[Dirk Pranke, 2013-01-18 00:29:02]

note that it's possible this'll cause a few tests to start failing due to the
different codepaths and performance. It'll probably make a bunch of tests be
less flaky, too.

[tony, 2013-01-18 00:37:06]

LGTM, please make sure that test_shell_tests all pass for you on Win or Mac (I
don't think the trybots run these tests).

[eroman, 2013-01-18 00:38:43]

lgtm

[tony, 2013-01-18 00:39:52]

When running tests under content_shell, can we also turn off the network proxy?

[Dirk Pranke, 2013-01-18 01:22:07]

On 2013/01/18 00:39:52, tony wrote:
> When running tests under content_shell, can we also turn off the network
proxy?

Eric can confirm, but I would imagine we would use the same proxy code that we
use in chrome (i.e., a different code path) by default. And, that might be the
right thing to do when running content_shell interactively (as it was the right
thing to do for test_shell). But it does make sense to turn it off for the
layout tests. I'll sync up w/ jochen and/or eric and look into it.

[Dirk Pranke, 2013-01-18 02:16:01]

test_shell_tests ran fine on mac and win.

[Dirk Pranke, 2013-02-07 03:30:32]

On 2013/01/18 02:16:01, Dirk Pranke wrote:
> test_shell_tests ran fine on mac and win.

wtf ... apparently I never actually landed this. Not sure how that happened.
Re-running try jobs and trying again.