Revert of Hook up ProximityAuthSystem in EasyUnlockService.

Revert of Hook up ProximityAuthSystem in EasyUnlockService. (patchset #7 id:160001 of https://codereview.chromium.org/1372283002/ )

Reason for revert:
MSAN test failure:
http://build.chromium.org/p/chromium.memory.fyi/builders/Linux%20MSan%20Tests/builds/10082

Original issue's description:
> Hook up ProximityAuthSystem in EasyUnlockService.
>
> ProximityAuthSystem is intended to replace the background page of the easy_unlock Chrome app.
> Currently, this functionality is implemented behind the kEnableBluetoothLowEnergyDiscovery flag.
>
> BUG=527558
> TEST=manual
>
> Committed: https://crrev.com/163fa44c84f8d4041f2d2e3b2fb359f3643b03c3
> Cr-Commit-Position: refs/heads/master@{#351707}

TBR=sacomoto@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=527558
Committed: https://crrev.com/7c1f91a89ddf578db224cd1874938236b93cbec8
Cr-Commit-Position: refs/heads/master@{#351721}

[Tim Song, 2015-10-01 04:15:01]

Created Revert of Hook up ProximityAuthSystem in EasyUnlockService.

[commit-bot: I haz the power, 2015-10-01 04:15:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1377313002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1377313002/1

[commit-bot: I haz the power, 2015-10-01 04:17:18]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-01 04:18:07]

Patchset 1 (id:??) landed as
https://crrev.com/7c1f91a89ddf578db224cd1874938236b93cbec8
Cr-Commit-Position: refs/heads/master@{#351721}