Record whether a SSL warning is caused by a self-signed cert

Record whether a SSL warning is caused by a self-signed cert

This adds the UMA call to record when SSL warnings are caused by self-
signed certs.

It also updates the histogram name: SSLNonAttackCauses is no longer
an appropriate name because a self-signed cert very well might be an
attack.

BUG=392310
R=palmer@chromium.org

Committed: https://crrev.com/05b83de45a179f95fca6c4c1bf08142f93268451
Cr-Commit-Position: refs/heads/master@{#311362}

[felt, 2015-01-13 22:18:18]

felt@chromium.org changed reviewers:
+ asvitkine@chromium.org

[felt, 2015-01-13 22:19:03]

Chris, Alexei, please review.

Chris: I'm really sorry to not have landed this a long time ago, after you
landed https://codereview.chromium.org/634033002/. I thought it was being
recorded already, but I was looking at the wrong histogram entry.

[Alexei Svitkine (slow), 2015-01-13 22:38:54]

The CQ bit was checked by asvitkine@chromium.org

[Alexei Svitkine (slow), 2015-01-13 22:38:54]

lgtm

[commit-bot: I haz the power, 2015-01-13 22:39:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/808053007/1

[commit-bot: I haz the power, 2015-01-13 23:47:53]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-13 23:48:50]

Patchset 1 (id:??) landed as
https://crrev.com/05b83de45a179f95fca6c4c1bf08142f93268451
Cr-Commit-Position: refs/heads/master@{#311362}