Revert 168384 "Use OwnPtrs for heap contains cache and persisten..."

Revert 168384 as it caused a serious crash (top #1 crasher on mac).

BUG=349842

> Use OwnPtrs for heap contains cache and persistent anchor. We were leaking the HeapContainsCache.
> 
> R=haraken@chromium.org, vegorov@chromium.org
> BUG=348629
> NOTRY=true
> 
> Review URL: https://codereview.chromium.org/183683017

TBR=ager@chromium.org

Review URL: https://codereview.chromium.org/180723022

git-svn-id: svn://svn.chromium.org/blink/trunk@168676 bbb929c8-8fbe-4397-9dbb-9b2b20218538