Revert 269798 "Only commit cookie changes in prerenders after a ..."

Revert 269798 "Only commit cookie changes in prerenders after a ..."

This broke prerender omnibox tests (Failing on tree, also failed on
trybot runs for the CL).

> Only commit cookie changes in prerenders after a prerender is shown
> Will create a PrerenderCookieStore for each prerender, retaining all cookie
> operations of a prerender until the prerender is shown to the user.
> Forces prerenders to be in a new render process by themselves for this to work.
> BUG=371003
> R=creis@chromium.org, davidben@chromium.org, erikwright@chromium.org, jam@chromium.org, jochen@chromium.org
> 
> Review URL: https://codereview.chromium.org/233353003

TBR=tburkard@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=269812

[mmenke, 2014-05-12 18:05:17]

Committed patchset #1 manually as r269812 (tree was closed).