Revert of Introduce LookupIterator::Restart() and use it

Revert of Introduce LookupIterator::Restart() and use it (patchset #2 id:20001 of https://codereview.chromium.org/1416053007/ )

Reason for revert:
Breaks test if rolled into Chromium: http://build.chromium.org/p/chromium.win/buildstatus?builder=Vista%20Tests%20%281%29&number=60441

Needed so the reverts applies cleanly and seems to be related to the offending CL.

Original issue's description:
> Introduce LookupIterator::Restart() and use it
>
> Committed: https://crrev.com/5676415b4add059b78f98a9a762d00c8d721dbcd
> Cr-Commit-Position: refs/heads/master@{#31483}

TBR=verwaest@chromium.org,jkummerow@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/984f8af8922d368755d9dd6e2537817d66ae4530
Cr-Commit-Position: refs/heads/master@{#31534}

[Michael Hablich, 2015-10-23 19:21:21]

Created Revert of Introduce LookupIterator::Restart() and use it

[commit-bot: I haz the power, 2015-10-23 19:21:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1418213003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1418213003/1

[commit-bot: I haz the power, 2015-10-23 19:22:00]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-23 19:22:27]

Patchset 1 (id:??) landed as
https://crrev.com/984f8af8922d368755d9dd6e2537817d66ae4530
Cr-Commit-Position: refs/heads/master@{#31534}