Revert of Revert of Follow up change for disabling out-of-box VK overscroll

Revert of Revert of Follow up change for disabling out-of-box VK overscroll (https://codereview.chromium.org/301923002/)

Reason for revert:
Reverting incorrect revert.

Proper revert committed in
http://src.chromium.org/viewvc/chrome?view=rev&revision=273467

Original issue's description:
> Revert of Follow up change for disabling out-of-box VK overscroll (https://codereview.chromium.org/298373002/)
> 
> Reason for revert:
> This CL broke VMTest on ChromiumOS bot:
> http://build.chromium.org/p/chromium.chromiumos/builders/ChromiumOS%20%28x86%29/builds/21999
> http://build.chromium.org/p/chromium.chromiumos/builders/ChromiumOS%20%28x86%29/builds/21999/steps/VMTest%20%28attempt%201%29/logs/stdio
> 
> Original issue's description:
> > Follow up change for disabling out-of-box VK overscroll
> > 
> > Have to use CoreOobeActor through OobeUI since WebUILoginDisplay is not created during out-of-box.
> > Removed changes in *LoginDisplay*.
> > 
> > BUG=363635
> > R=ygorshenin@chromium.org
> > 
> > Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=273241
> 
> TBR=ygorshenin@chromium.org,nkostylev@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=363635
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=273466

TBR=ygorshenin@chromium.org,tzik@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=363635
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=273472

[Nikita (slow), 2014-05-29 14:10:48]

Created Revert of Revert of Follow up change for disabling out-of-box VK
overscroll

[commit-bot: I haz the power, 2014-05-29 14:11:56]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/nkostylev@chromium.org/301163002/1

[commit-bot: I haz the power, 2014-05-29 14:14:34]

Change committed as 273472