Remove #if ENABLE(OILPAN) around DEFINE_STATIC_LOCAL

This CL removes unnecessary #if ENABLE(OILPAN)s by:

- using OwnPtrWillBePersistent for static on-heap objects
- using DEFIN_STATIC_REF_WILL_BE_PERSISTENT

BUG=340522

Review URL: https://codereview.chromium.org/359283004

git-svn-id: svn://svn.chromium.org/blink/trunk@177193 bbb929c8-8fbe-4397-9dbb-9b2b20218538