Revert 190584 "Alternate NTP Mac: Show overlay at fixed position"

Revert 190584 "Alternate NTP Mac: Show overlay at fixed position"

Speculative revert to see this fixes the Mac startup perf regression.

BUG=224002
> Alternate NTP Mac: Show overlay at fixed position
> 
> Previously the overlay was shown at the bottom of the toolbar. The height of
> the bookmark bar changes if the bookmark bar is attached. This meant that the
> overlay would change positions (relative to the omnibox) depending on the
> bookmark bar's attached state.
> 
> With this CL we now show the overlay at the fixed offset from the omnibox.
> 
> One side effect of this is that the bottom of the toolbar can no longer act
> as a separator for the overlay. I've changed the overlay to draw its own
> separator.
> 
> Screenshot: http://i.imgur.com/ub9gfDo.png
> 
> BUG=173475, 174077
> TBR=sky@chromium.org
> 
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=190213
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=190519
> 
> Review URL: https://chromiumcodereview.appspot.com/12674019

TBR=sail@chromium.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=190732

[sail, 2013-03-26 19:33:43]

Committed patchset #1 manually as r190732.