Revert of Delete session cookies immediately after loading the cookie DB.

Revert of Delete session cookies immediately after loading the cookie DB. (patchset #4 id:120001 of https://codereview.chromium.org/1097593002/)

Reason for revert:
This CL broke the Win7 Tests (dbg)(1) bot.

https://build.chromium.org/p/chromium.win/builders/Win7%20Tests%20%28dbg%29%281%29/builds/37364

Original issue's description:
> Delete session cookies immediately after loading the cookie DB.
>
> Previously, the session cookies were deleted after all cookies were loaded into
> memory. This allows for a race condition where new session cookies are inserted
> into the database while the cookies are being loaded into memory, which causes
> the new session cookies to also be deleted.
>
> BUG=
>
> Committed: https://crrev.com/ca924dcfb4f3c6b89e0c40898e42aec349b6b843
> Cr-Commit-Position: refs/heads/master@{#326672}

TBR=erikwright@chromium.org,erikchen@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Committed: https://crrev.com/8c6775990e9b343d133b2f1560f4d45be445426c
Cr-Commit-Position: refs/heads/master@{#326694}

[Justin Donnelly, 2015-04-23 23:56:22]

Created Revert of Delete session cookies immediately after loading the cookie
DB.

[commit-bot: I haz the power, 2015-04-23 23:57:09]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1077963006/1

[commit-bot: I haz the power, 2015-04-23 23:58:22]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-23 23:59:22]

Patchset 1 (id:??) landed as
https://crrev.com/8c6775990e9b343d133b2f1560f4d45be445426c
Cr-Commit-Position: refs/heads/master@{#326694}