Revert of Refactor connection_security into SecurityStateModel (patchset #17 id:36000...

Revert of Refactor connection_security into SecurityStateModel (patchset #17 id:360001 of https://codereview.chromium.org/1314843007/ )

Reason for revert:
We need to call SecurityStateChanged() in a few more places to avoid a crash and some UI bugs. See bugs 529664 and 529872.

Original issue's description:
> Refactor connection_security into SecurityStateModel
>
> This CL refactors the connection_security namespace (a namespace of
> statics) into SecurityStateModel, a class attached to a WebContents that
> drives the security UI for that WebContents. The SecurityStateModel
> provides high-level security information about a page or request, with
> the goal of reducing code duplication across various security UI
> elements.
>
> In this first CL, I've introduced the SecurityStateModel and am using it
> to drive the omnibox/lock icon, but have not yet adapted WebsiteSettings
> to use a SecurityStateModel.
>
> BUG=528034
> TBR=sky@chromium.org
>
> Committed: https://crrev.com/83a81afbef8f265815cb6c6a48690511825a1ce5
> Cr-Commit-Position: refs/heads/master@{#347775}

TBR=palmer@chromium.org,lgarron@chromium.org,pkasting@chromium.org,tedchoc@chromium.org,avi@chromium.org,sky@chromium.org,dzhioev@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=528034

Review URL: https://codereview.chromium.org/1324293003

Cr-Commit-Position: refs/heads/master@{#347980}