Revert 159356 "Revert r158912 due to tcmalloc corruption."

> Revert r158912 due to tcmalloc corruption.
>
> This also reverts r159311, which fixed a use-after-free introduced in
> r158912.
>
> BUG=305884,305080,301514
> R=abarth@chromium.org, jochen@chromium.org
>
> Review URL: https://codereview.chromium.org/26763003

R=abarth@chromium.org, dcheng@chromium.org

Review URL: https://codereview.chromium.org/26977005

git-svn-id: svn://svn.chromium.org/blink/trunk@159525 bbb929c8-8fbe-4397-9dbb-9b2b20218538