Revert 179213 "Oilpan: Convert some Resource raw pointer members..."

This CL caused a lot of crashes in webkit_unit_tests in oilpan bots:

http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac%20Oilpan%20%28dbg%29/builds/4024

> Oilpan: Convert some Resource raw pointer members to Member<> or Persistent<>.
> 
> BUG=393516
> 
> Review URL: https://codereview.chromium.org/416203003

TBR=tkent@chromium.org

Review URL: https://codereview.chromium.org/432623002

git-svn-id: svn://svn.chromium.org/blink/trunk@179268 bbb929c8-8fbe-4397-9dbb-9b2b20218538