Merge to M39: Correct manual proxy selection for WebSockets.

Correct manual proxy selection for WebSockets.

When an HTTPS and/or HTTP proxy was manually configured, WebSocket
connections were mistakenly going direct to the origin server.

According to RFC6455, WebSocket connections should prefer SOCKS proxies,
then HTTPS, then HTTP proxies in that order. Fix the behaviour when
proxies are manually selected to match.

BUG=426736
TEST=net_unittests, manual
R=eroman@chromium.org

Committed: https://chromium.googlesource.com/chromium/src/+/07620c32441e264cf108943282536d8b41fca248

[Adam Rice, 2014-11-07 10:35:49]

ricea@chromium.org changed reviewers:
+ eroman@chromium.org

[Adam Rice, 2014-11-07 10:40:59]

+eroman amineer@ says he's on the fence about whether to merge this to M39, but
he's prepared to allow it.

I think it's a low-risk merge, and while the number of impacted users is
relatively small, they're having a bad time.

Let me know what you think.

[eroman, 2014-11-07 22:15:21]

I am fine with merging this.
I don't expect it will cause any problems (the changes are fairly simple).

[eroman, 2014-11-07 22:15:26]

lgtm

[eroman, 2014-11-07 22:16:01]

(You still need merge approval; my LGTM was just to indicate that I am on
board).

[Adam Rice, 2014-11-08 11:15:36]

Committed patchset #1 (id:1) manually as
07620c32441e264cf108943282536d8b41fca248 (presubmit successful).