Revert of Move prefix_set and parts of s_b_util into a new component safe_browsing_db.

Revert of Move prefix_set and parts of s_b_util into a new component safe_browsing_db. (patchset #7 id:120001 of https://codereview.chromium.org/1399843003/ )

Reason for revert:
Broke the Windows x64 GN builders:

http://build.chromium.org/p/chromium.win/buildstatus?builder=Win%20x64%20GN&number=7560

Original issue's description:
> Move prefix_set and parts of safe_browsing_util into a new component safe_browsing_db.
>
> This component will hold the new implementation for the
> next version (pver4) of the update protocol and DB.
>
> BUG=543161
>
> Committed: https://crrev.com/607ee298239a88fa0823c3aea10bcee83eff855a
> Cr-Commit-Position: refs/heads/master@{#355654}

TBR=nparker@chromium.org,noelutz@chromium.org,droger@chromium.org,thestig@chromium.org,blundell@chromium.org,rsleevi@chromium.org,vakh@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=543161
Committed: https://crrev.com/1f66733b39fdc5499c034497a3747a97b5bcc0db
Cr-Commit-Position: refs/heads/master@{#355659}

[DaleCurtis, 2015-10-22 22:36:15]

Created Revert of Move prefix_set and parts of s_b_util into a new component
safe_browsing_db.

[commit-bot: I haz the power, 2015-10-22 22:36:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1420143002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1420143002/1

[commit-bot: I haz the power, 2015-10-22 22:38:44]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-22 22:39:36]

Patchset 1 (id:??) landed as
https://crrev.com/1f66733b39fdc5499c034497a3747a97b5bcc0db
Cr-Commit-Position: refs/heads/master@{#355659}

[vakh (old account. dont use), 2015-10-22 22:55:29]

Apologies for breaking the build. Other than all the bots passing, is there
another way to avoid this in the future?

[DaleCurtis, 2015-10-23 01:09:44]

The problem is we're missing x64 GN CQ bots right now which would have caught
this.... https://code.google.com/p/chromium/issues/detail?id=486089 tracks this
I think :/