Enable Oilpan for DOMError and FileError

This is a follow-up CL for https://codereview.chromium.org/588073003/, which shipped Oilpan for core/fileapi/. This CL just ships Oilpan for DOMError and FileError in a pretty straightforward way.

BUG=340522

Review URL: https://codereview.chromium.org/615473002

git-svn-id: svn://svn.chromium.org/blink/trunk@183043 bbb929c8-8fbe-4397-9dbb-9b2b20218538